pith. sign in

arxiv: 2604.17704 · v1 · submitted 2026-04-20 · 🪐 quant-ph

Quantum Spectroscopy with Undetected Photons for Biomolecular Sensing in the Mid-Infrared

Mahya Mohammadi , Meryem-Nur Duman , Isa Ahmadalidokht , Mohammad Sadraeian , Christopher G. Poulton , Alexander S. Solntsev , Irina V. Kabakova This is my paper

Pith reviewed 2026-05-10 05:38 UTC · model grok-4.3

classification 🪐 quant-ph
keywords quantum spectroscopyundetected photonsmid-infraredprotein sensinginterference visibilityamide bandsbiomolecular detection
0
0 comments X

The pith

A numerical model of a double-pass quantum interferometer reproduces protein mid-infrared absorption spectra from visible-light visibility measurements.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper takes classical Fourier-transform infrared absorption data from two proteins and inserts it into a numerical simulation of a double-pass quantum interferometer that uses undetected mid-infrared photons. By varying crystal length, sample length, and mirror position, the model produces visibility spectra of the visible signal beams that closely track the original mid-infrared absorption features, including shifts linked to temperature-driven changes in protein secondary structure. This establishes that the quantum setup can in principle perform biomolecular sensing in the mid-infrared while relying only on visible sources and detectors.

Core claim

Embedding measured mid-infrared absorption spectra into the numerical model of the double-pass quantum interferometer yields visibility spectra that reproduce the protein absorption bands nearly identically and register temperature-induced alterations to secondary structure, thereby supplying concrete design rules for a practical quantum spectrometer operating with visible light.

What carries the argument

Double-pass quantum interferometer whose visibility pattern, formed by the visible signal photons, encodes the absorption experienced by the undetected mid-infrared idler photons after the classical absorption data is inserted into the model.

If this is right

  • Optimal values of nonlinear-crystal length, sample thickness, and mirror-sample distance produce maximum contrast at the specific amide I-II bands.
  • The visibility spectra register temperature-induced changes to the protein secondary structure.
  • The approach supplies practical design rules for quantum bio-spectroscopy that uses only visible sources and detectors.
  • The same model framework applies to both bovine serum albumin and N-terminal pro-brain natriuretic peptide.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • The method could be tested on other biomolecules whose mid-infrared signatures are already known from classical spectra.
  • Hybrid classical-quantum workflows might accelerate validation of new sensing geometries before hardware is built.
  • Portable devices for protein diagnostics could become feasible if visible-light components replace mid-infrared sources and detectors.

Load-bearing premise

The numerical model correctly translates the embedded classical absorption data into the quantum interference visibility without needing a physical quantum experiment on the actual protein samples.

What would settle it

Build the double-pass interferometer with the protein sample in the idler path and record whether the measured visibility spectrum at the amide I-II bands matches the simulated spectrum derived from the classical FTIR data.

Figures

Figures reproduced from arXiv: 2604.17704 by Alexander S. Solntsev, Christopher G. Poulton, Irina V. Kabakova, Isa Ahmadalidokht, Mahya Mohammadi, Meryem-Nur Duman, Mohammad Sadraeian.

Figure 1
Figure 1. Figure 1: Conceptual scheme for retrieving mid-infrared (MIR) spectroscopic information of proteins using visible (VIS) / near-infrared (NIR) photons. A liquid biopsy sample containing proteins exhibits characteristic vibrational absorption features in the MIR spectral region, such as the Amide I and Amide II bands. In the proposed approach, correlated photon pairs are generated through spontaneous parametric down-c… view at source ↗
Figure 2
Figure 2. Figure 2: SPDC interferometer configuration and phase-matching conditions. (a) Double-pass SPDC configuration consisting of a nonlinear crystal, an off-axis parabolic mirror (OAPM), [PITH_FULL_IMAGE:figures/full_fig_p019_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: FTIR results (a) Comparison of the FTIR spectra of BSA and NT-proBNP samples, highlighting differences in their molecular vibrations and characteristic bands. (b) Temperature-dependent changes in BSA spectra observed at 24 °C and 68 °C, showing structural modifications with heating [PITH_FULL_IMAGE:figures/full_fig_p020_3.png] view at source ↗
Figure 5
Figure 5. Figure 5: Optimisation of experimental parameters using weighted visibility β: (a) Weighted visibility β as a function of the nonlinear crystal length L, showing an optimal range of 5–6 mm. (b) The weighted visibility β for a varying optical path length of the sample Lm identifies the optimal sample length Lm = 6 μm. For each case, the corresponding interference fringe patterns at the maximum and minimum values of β… view at source ↗
Figure 6
Figure 6. Figure 6: The weighted visibility β for a varying crystal–mirror separation La indicates that the optimal separation is La = −8.75 mm [PITH_FULL_IMAGE:figures/full_fig_p020_6.png] view at source ↗
read the original abstract

We investigate quantum spectroscopy with undetected photons for protein detection in the mid-infrared spectral region. Classical Fourier-transform infrared spectroscopy of protein samples (bovine serum albumin and N-terminal pro-brain natriuretic peptide) is used as reference to define the sample's mid-infrared absorption, which is then embedded in a numerical model of a double-pass quantum interferometer. We analyse parameters that influence visibility of the interference pattern formed by the signal beams, including the length of nonlinear crystal, sample length and mirror-sample distance. This leads us to a practical quantum spectrometer design with optimal image contrast at the specific amide I-II spectral bands. The simulated visibility spectra reproduce nearly identically the protein absorption features in the mid-IR and reveal temperature-induced changes to the protein secondary structure. Overall, this provides practical design rules for future quantum bio-spectroscopy applications that use only visible wavelength sources and detectors.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

1 major / 2 minor

Summary. The manuscript presents a numerical study of quantum spectroscopy with undetected photons for mid-infrared biomolecular sensing. Classical FTIR absorption spectra of proteins (bovine serum albumin and N-terminal pro-brain natriuretic peptide) are used as reference data and embedded into a model of a double-pass quantum interferometer. The authors examine the effects of nonlinear crystal length, sample length, and mirror-sample distance on interference visibility, optimize these for contrast at the amide I-II bands, and report that the resulting simulated visibility spectra closely reproduce the classical protein absorption features, including temperature-induced shifts in secondary structure. The work concludes with practical design rules for quantum bio-spectrometers that rely only on visible sources and detectors.

Significance. If the numerical model is complete, the results would demonstrate a viable route to mid-IR protein sensing without mid-IR hardware, which has clear practical value for biomolecular applications. The parameter optimization and use of real classical reference data as input are strengths, as is the reported sensitivity to secondary-structure changes. However, the absence of any experimental validation of the quantum interferometer with these samples, combined with the simulation-only nature of the claims, limits the current impact to a design study rather than a demonstrated technique.

major comments (1)
  1. [Numerical model / quantum spectrometer design] The numerical model of the double-pass interferometer (described in the section on the quantum spectrometer design and simulations) embeds only the amplitude loss derived from classical absorption data. The visibility in undetected-photon schemes depends on the full complex transmission t(ω) = |t(ω)| exp(i φ(ω)) of the idler; the phase φ(ω) must be obtained via Kramers-Kronig relations from the measured absorption or from the real refractive index. If the model omits this phase (or uses only |t|), the simulated visibility spectra cannot be guaranteed to reproduce the absorption features at the amide bands, undermining the central claim that they match 'nearly identically' and reveal temperature-induced changes.
minor comments (2)
  1. [Abstract] The abstract states that the simulated visibility spectra 'reproduce nearly identically' the protein features but provides no quantitative metric (e.g., RMS deviation or correlation coefficient) for this agreement; adding such a measure would strengthen the presentation.
  2. [Abstract and conclusion] The parameter values that achieve the 'optimal image contrast' (crystal length, sample length, mirror distance) are not stated numerically in the abstract or conclusion; including them would make the design rules immediately usable.

Simulated Author's Rebuttal

1 responses · 0 unresolved

We thank the referee for their careful reading of the manuscript and for highlighting an important technical point regarding the numerical model. We address the comment below and have revised the work to incorporate the suggested improvement.

read point-by-point responses

  1. Referee: The numerical model of the double-pass interferometer (described in the section on the quantum spectrometer design and simulations) embeds only the amplitude loss derived from classical absorption data. The visibility in undetected-photon schemes depends on the full complex transmission t(ω) = |t(ω)| exp(i φ(ω)) of the idler; the phase φ(ω) must be obtained via Kramers-Kronig relations from the measured absorption or from the real refractive index. If the model omits this phase (or uses only |t|), the simulated visibility spectra cannot be guaranteed to reproduce the absorption features at the amide bands, undermining the central claim that they match 'nearly identically' and reveal temperature-induced changes.

    Authors: We agree with the referee that the visibility in the undetected-photon interferometer depends on the full complex transmission coefficient t(ω) of the idler beam. Our original implementation extracted only the amplitude |t(ω)| from the measured FTIR absorption spectra while omitting the dispersive phase φ(ω). To correct this, we have now applied Kramers-Kronig relations to the absorption data to obtain φ(ω) and have recomputed the interference visibility using the complete complex t(ω). The revised simulations show that the visibility spectra still reproduce the amide I and II absorption features nearly identically, including the temperature-induced secondary-structure shifts reported for both proteins. We have added a new subsection describing the Kramers-Kronig procedure, the resulting phase spectra, and the updated visibility curves, together with a brief discussion of the minor quantitative differences introduced by the phase term. These changes strengthen the central claim without altering the overall conclusions or the practical design rules. revision: yes

Circularity Check

0 steps flagged

No significant circularity: classical FTIR absorption embedded as independent input into interferometer model

full rationale

The derivation takes measured classical mid-IR absorption spectra (from FTIR on BSA and NT-proBNP samples) as external reference data and embeds them into a numerical model of the double-pass quantum interferometer. Simulated visibility spectra are then computed from this model and shown to reproduce the input absorption features at amide bands. This is a forward simulation using independent external benchmarks rather than any self-definition, parameter fitting to quantum outputs, or load-bearing self-citation chain. No equations reduce the visibility result to the input by construction; the reproduction tests the model's fidelity to the embedded physics. The paper remains self-contained against the cited classical data.

Axiom & Free-Parameter Ledger

0 free parameters · 1 axioms · 0 invented entities

The approach assumes classical absorption spectra transfer directly into the quantum model and that the interferometer geometry can be optimized via simulation alone.

axioms (1)
  • domain assumption Classical mid-IR absorption data can be directly embedded into the quantum interferometer model without additional quantum corrections or sample-specific effects.
    Stated in the abstract as the basis for the numerical model.

pith-pipeline@v0.9.0 · 5479 in / 1123 out tokens · 28016 ms · 2026-05-10T05:38:39.678724+00:00 · methodology

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Reference graph

Works this paper leans on

62 extracted references · 62 canonical work pages

  1. [1]

    Introduction The mid-infrared (MIR) range of the electromagnetic spectrum, corresponding to wavelengths between approximately 2.5 and 25 μm (4000 to 400 cm⁻¹), is of great importance for environmental sensing, biomolecular detection, and defence applications [1, 2]. This spectral region encompasses the fundamental vibrational modes of most chemical bonds ...

    work page

  2. [2]

    The core principle enabling QSUP, induced coherence without induced emission , was introduced in the 1990s

    Principles of Quantum Spectroscopy with Undetected Photons Quantum spectroscopy with undetected photons (QSUP) originates from early advances in nonlinear optics, including the first demonstrations of SPDC in the late 1960s and early 1970s, 4 which established the generation of correlated photon pairs for quantum measurements [18]. The core principle enab...

    work page 2014

  3. [3]

    Phosphate buffer solution (PBS) was purchased from ThermoFisher Scientific (Scoresby, Victoria)

    Sample preparation and FTIR measurement Lyophilized bovine serum albumin was purchased from Merck (Bayswater, Victoria) and Recombinant Human NT -proBNP was purchased from Millennium science (Mulgrave, Victoria), both proteins were used as supplied. Phosphate buffer solution (PBS) was purchased from ThermoFisher Scientific (Scoresby, Victoria). Protein so...

    work page

  4. [4]

    The intensity distribution of the signal beams interference in the presence of a biological sample is given by equation (3)

    QSUP simulations We now consider the use of QSUP for label-free biomolecular detection and dynamic protein structure studies in the MIR. The intensity distribution of the signal beams interference in the presence of a biological sample is given by equation (3). Here we use the ATR -FTIR measurement data for the sample transmissivity τ to test feasibility ...

    work page

  5. [5]

    Discussion and Conclusion Our results demonstrate a close agreement between QSUP and FTIR results for the two standard proteins and can, in principle, be extended to sensing of other biomolecules in aqueous solutions. By embedding experimentally measured FTIR spectra of BSA and NT-proBNP into a numerical model of a double-pass interferometer, we numerical...

    work page

  6. [6]

    Data availability statement All the data supporting this study are available upon request to the corresponding authors

    work page

  7. [7]

    An, D. et al. Mid-infrared absorption spectroscopy with enhanced detection performance for biomedical applications. Appl. Spectrosc. Rev. 58, 834–868 (2023). 17

    work page 2023

  8. [8]

    Fakhlaei, R. et al. Application, challenges and future prospects of recent nondestructive techniques based on the electromagnetic spectrum in food quality and safety. Food Chem. 441, 138402 (2024)

    work page 2024

  9. [9]

    Baker, M. J. et al. Using Fourier transform IR spectroscopy to analyze biological materials. Nat. Protoc. 9, 1771–1791 (2014)

    work page 2014

  10. [10]

    Yang, H., Yang, S., Kong, J., Dong, A. & Yu, S. Obtaining information about protein secondary structures in aqueous solution using Fourier transform IR spectroscopy. Nat. Protoc. 10, 382– 396 (2015)

    work page 2015

  11. [11]

    S., Ahmed, Z

    Myshakina, N. S., Ahmed, Z. & Asher, S. A. Dependence of amide vibrations on hydrogen bonding. J. Phys. Chem. B 112, 11873–11877 (2008)

    work page 2008

  12. [12]

    S., Kitaeva, G

    Solntsev, A. S., Kitaeva, G. K., Naumova, I. I. & Penin, A. N. Characterization of aperiodic domain structure in lithium niobate by spontaneous parametric down-conversion spectroscopy. Laser Phys. Lett. 12, 095702 (2015)

    work page 2015

  13. [13]

    Elefante, A. et al. Recent progress in short and mid-infrared single-photon generation: a review. Optics 4, 13–38 (2023)

    work page 2023

  14. [14]

    & Keiding, S

    Ramsay, J., Dupont, S. & Keiding, S. R. Pulse -to-pulse noise reduction in infrared supercontinuum spectroscopy: polarization and amplitude fluctuations. Laser Phys. Lett. 11, 095702 (2014)

    work page 2014

  15. [15]

    Cheng, X. et al. Design of spontaneous parametric down -conversion in integrated hybrid Si x Ny -PPLN waveguides. Opt. Express 27, 30773 (2019)

    work page 2019

  16. [16]

    W., Ramelow, S., Brandstetter, M

    Gattinger, P., Schell, A. W., Ramelow, S., Brandstetter, M. & Zorin, I. Quantum Fourier transform infrared spectroscopy: evaluation, benchmarking, and prospects. Appl. Spectrosc. 79, 1737–1746 (2025)

    work page 2025

  17. [17]

    A., Paterova, A

    Kalashnikov, D. A., Paterova, A. V ., Kulik, S. P. & Krivitsky, L. A. Infrared spectroscopy with visible light. Nat. Photonics 10, 98–101 (2016)

    work page 2016

  18. [18]

    V ., Toa, Z

    Paterova, A. V ., Toa, Z. S. D., Yang, H. & Krivitsky, L. A. Broadband quantum spectroscopy at the fingerprint mid-infrared region. ACS Photonics 9, 2151–2159 (2022)

    work page 2022

  19. [19]

    Kumar, M. et al. Controlling visibility in nonlinear interferometry for spectroscopy with undetected photons. APL Photonics 10, 106121 (2025). 18

    work page 2025

  20. [20]

    Moreva, E. et al. Quantum photonics sensing in biosystems. APL Photonics 10, 010902 (2025)

    work page 2025

  21. [21]

    & Mohammadi, H

    Samimi, S., Ghasemi, Z. & Mohammadi, H. Quantum -enhanced imaging and metrology with undetected photons via squeezed-light homodyne detection. Sci. Rep. 15, 42966 (2025)

    work page 2025

  22. [22]

    Hashimoto, K. et al. Fourier-transform infrared spectroscopy with undetected photons from high-gain spontaneous parametric down-conversion. Commun. Phys. 7, 217 (2024)

    work page 2024

  23. [23]

    S., Kitaeva, G

    Solntsev, A. S., Kitaeva, G. Kh., Naumova, I. I. & Penin, A. N. Measurement of the extraordinary refractive index dispersion in the MIR for Mg:Nd:LiNb O₃ crystals by the use of quasi-phase-matching in a random 1D domain structure. Appl. Phys. B 99, 197–201 (2010)

    work page 2010

  24. [24]

    Burnham, D. C. & Weinberg, D. L. Observation of simultaneity in parametric production of optical photon pairs. Phys. Rev. Lett. 25, 84–87 (1970)

    work page 1970

  25. [25]

    Quantum effects in one -photon and two-photon interference

    Mandel, L. Quantum effects in one -photon and two-photon interference. Rev. Mod. Phys. 71, S274–S282 (1999)

    work page 1999

  26. [26]

    Lemos, G. B. et al. Quantum imaging with undetected photons. Nature 512, 409–412 (2014)

    work page 2014

  27. [27]

    Lahiri, M., Lapkiewicz, R., Lemos, G. B. & Zeilinger, A. Theory of quantum imaging with undetected photons. Phys. Rev. A 92, 013832 (2015)

    work page 2015

  28. [28]

    V ., Maniam, S

    Paterova, A. V ., Maniam, S. M., Yang, H., Grenci, G. & Krivitsky, L. A. Hyperspectral infrared microscopy with visible light. Sci. Adv. 6, eabd0460 (2020)

    work page 2020

  29. [29]

    Placke, M. et al. Mid-IR hyperspectral imaging with undetected photons. in Quantum 2.0 Conference and Exhibition QTu4C.4 (Optica Publishing Group, Washington, D.C., 2024)

    work page 2024

  30. [30]

    M., Avery, E

    Kviatkovsky, I., Chrzanowski, H. M., Avery, E. G., Bartolomaeus, H. & Ramelow, S. Microscopy with undetected photons in the mid-infrared. Sci. Adv. 6, eabd0264 (2020)

    work page 2020

  31. [31]

    Haase, B. E. et al. Phase-quadrature quantum imaging with undetected photons. Opt. Express 31, 143 (2023)

    work page 2023

  32. [32]

    Neves, S. et al. Detection of organic gases in air via quantum Fourier-transform mid-infrared spectroscopy. in Quantum 2.0 Conference and Exhibition QTh4C.7 (Optica Publishing Group, Washington, D.C., 2024)

    work page 2024

  33. [33]

    Kurita, T. et al. Quantum infrared attenuated total reflection spectroscopy. Phys. Rev. Appl. 23, 014061 (2025). 19

    work page 2025

  34. [34]

    Haase, B. et al. Spontaneous parametric down-conversion of photons at 660 nm to the terahertz and sub-terahertz frequency range. Opt. Express 27, 7458 (2019)

    work page 2019

  35. [35]

    S., Kumar, P., Pertsch, T., Sukhorukov, A

    Solntsev, A. S., Kumar, P., Pertsch, T., Sukhorukov, A. A. & Setzpfandt, F. Quantum spectroscopy on a nonlinear photonic chip. in 2017 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe -EQEC) 1–1 (IEEE, 2017)

    work page 2017

  36. [36]

    Funding Declaration The authors acknowledge the financial support from Australian Research Council Centre of Excellence in Quantum Biotechnology (CE230100021) and IRTP from UTS

    work page

  37. [37]

    CGP contributed to analysis of results

    Author contribution statement ASS and IVK devised the project, MM implemented numerical modelling, MM and MND obtained FTIR results of protein samples, IA and MS consulted on experimental planning. CGP contributed to analysis of results. All authors contributed to the results analysis, manuscript writing and editing

    work page

  38. [38]

    Additional Information The authors declare no competing interests

    work page

  39. [39]

    Conceptual scheme for retrieving mid -infrared (MIR) spectroscopic information of proteins using visible (VIS) / near-infrared (NIR) photons

    Figure legends Figure 1. Conceptual scheme for retrieving mid -infrared (MIR) spectroscopic information of proteins using visible (VIS) / near-infrared (NIR) photons. A liquid biopsy sample containing proteins exhibits characteristic vibrational absorption features in the MIR spectral region, such as the Amide I and Amide II bands. In the proposed approac...

    work page 2007

  40. [40]

    G., Pahlow, S

    Mayerhöfer, T. G., Pahlow, S. & Popp, J. The Bouguer–Beer–Lambert law: shining light on the obscure. ChemPhysChem 21, 2029–2046 (2020)

    work page 2029

  41. [41]

    & Yan, Y .-B

    Zhang, J. & Yan, Y .-B. Probing conformational changes of proteins by quantitative second - derivative infrared spectroscopy. Anal. Biochem. 340, 89–98 (2005)

    work page 2005

  42. [42]

    & Yan, H

    Yuan, B., Murayama, K. & Yan, H. Study of thermal dynamics of defatted bovine serum albumin in D 2O Solution by Fourier transform infrared spectra and evolving factor analysis. Appl. Spectrosc. 61, 921–927 (2007)

    work page 2007

  43. [43]

    & Caughey, W

    Dong, A., Huang, P. & Caughey, W. S. Protein secondary structures in water from second - derivative amide I infrared spectra. Biochemistry 29, 3303–3308 (1990)

    work page 1990

  44. [44]

    N., Baikalov, I

    Kalnin, N. N., Baikalov, I. A. & Venyaminov, S. Yu. Quantitative IR spectrophotometry of peptide compounds in water (H2O) solutions. III. Estimation of the protein secondary structure. Biopolymers 30, 1273–1280 (1990)

    work page 1990

  45. [45]

    Venyaminov, S. Yu. & Kalnin, N. N. Quantitative IR spectrophotometry of peptide compounds in water (H 2O) solutions. I. Spectral parameters of amino acid residue absorption bands. Biopolymers 30, 1243–1257 (1990)

    work page 1990

  46. [46]

    Venyaminov, S. Yu. & Kalnin, N. N. Quantitative IR spectrophotometry of peptide compounds in water (H 2O) solutions. II. Amide absorption bands of polypeptides and fibrous proteins in α‐, β‐, and random coil conformations. Biopolymers 30, 1259–1271 (1990)

    work page 1990

  47. [47]

    Chou, P. Y . & Fasman, G. D. β-turns in proteins. J. Mol. Biol. 115, 135–175 (1977)

    work page 1977

  48. [48]

    & Uspenskaya, M

    Usoltsev, D., Sitnikova, V ., Kajava, A. & Uspenskaya, M. Systematic FTIR spectroscopy study of the secondary structure changes in human serum albumin under various denaturation conditions. Biomolecules 9, 359 (2019)

    work page 2019

  49. [49]

    & Huang, H

    Zhou, X., He, Z. & Huang, H. Secondary structure transitions of Bovine serum albumin induced by temperature variation. Vib. Spectrosc. 92, 273–279 (2017). 29

    work page 2017

  50. [50]

    Holloway, P. W. & Mantsch, H. H. Structure of cytochrome b5 in solution by Fourier-transform infrared spectroscopy. Biochemistry 28, 931–935 (1989)

    work page 1989

  51. [51]

    & Komorowsk, M

    Olsztyska-Janus, S., Gsior-Gogowska, M., Szymborska-Maek, K., Czarnik-Matusewicz, B. & Komorowsk, M. Specific applications of vibrational spectroscopy in biomedical engineering. In Biomedical Engineering, Trends, Research and Technologies (InTech, 2011)

    work page 2011

  52. [52]

    Srour, B., Bruechert, S., Andrade, S. L. A. & Hellwig, P. Secondary structure determination by means of ATR-FTIR spectroscopy. Methods Mol. Biol. 1635, 195–203 (2017)

    work page 2017

  53. [53]

    L., Köhler, U

    Casal, H. L., Köhler, U. & Mantsch, H. H. Structural and conformational changes of β- lactoglobulin B: an infrared spectroscopic study of the effect of pH and temperature. Biochim. Biophys. Acta 957, 11–20 (1988)

    work page 1988

  54. [54]

    Infrared difference spectroscopy

    Grdadolnik, J. Infrared difference spectroscopy. Vib. Spectrosc. 31, 279–288 (2003)

    work page 2003

  55. [55]

    Bauelos, S., Arrondo, J. L. R., Goi, F. M. & Pifat, G. Surface-core relationships in human low density lipoprotein as studied by infrared spectroscopy. J. Biol. Chem. 270, 9192–9196 (1995)

    work page 1995

  56. [56]

    & Muga, A

    Bañuelos, S. & Muga, A. Structural requirements for the association of native and partially folded conformations of α-lactalbumin with model membranes. Biochemistry 35, 3892–3898 (1996)

    work page 1996

  57. [57]

    & Naumann, D

    Reinstädler, D., Fabian, H., Backmann, J. & Naumann, D. Refolding of thermally and urea- denatured ribonuclease a monitored by time-resolved FTIR spectroscopy. Biochemistry 35, 15822–15830 (1996)

    work page 1996

  58. [58]

    & Krimm, S

    Reisdorf, , William C. & Krimm, S. Infrared amide I band of the coiled coil. Biochemistry 35, 1383–1386 (1996)

    work page 1996

  59. [59]

    H., Woodruff, W

    Gilmanshin, R., Williams, S., Callender, R. H., Woodruff, W. H. & Dyer, R. B. Fast events in protein folding: Relaxation dynamics of secondary and tertiary structure in native apomyoglobin. Proc. Natl Acad. Sci. 94, 3709–3713 (1997)

    work page 1997

  60. [60]

    G., Feldhoff, R

    Reed, R. G., Feldhoff, R. C., Clute, O. L. & Peters, T. Fragments of bovine serum albumin produced by limited proteolysis : conformation and ligand binding. Biochemistry 14, 4578– 4583 (1975)

    work page 1975

  61. [61]

    WETZEL, R. et al. Temperature behaviour of human serum albumin. Eur. J. Biochem. 104, 469–478 (1980)

    work page 1980

  62. [62]

    Carter, D. C. & Ho, J. X. Structure of serum albumin. Advances in Protein Chemistry 45, 153– 203 (1994)

    work page 1994