Protein random coil — FTIR absorption peaks and assignments
These are the characteristic FTIR wavenumbers where Protein random coil tends to absorb, compiled from published literature and ranked by supporting evidence. Each assignment is traceable to a source (DOI) and cross-validated against our 130,000+ reference spectra and knowledge graph.
Backed by 8 cited sources
Quick answer
Protein random coil is usually assigned by looking for a recurring cluster of characteristic peaks rather than one exact textbook number. The table below shows where the literature most often places this group in FTIR, ranked by accumulated evidence.
Characteristic FTIR peaks for Protein random coil
| Wavenumber (cm⁻¹) | Supporting facts | Cited sources | Top confidence |
|---|---|---|---|
| 1645 | 11 | 10 | 1.0 |
| 1650 | 8 | 8 | 1.0 |
| 1639 | 3 | 3 | 1.0 |
| 1647 | 3 | 3 | 1.0 |
| 1640 | 3 | 3 | 1.0 |
| 1644 | 2 | 2 | 1.0 |
| 1660 | 2 | 2 | 1.0 |
| 1648 | 2 | 2 | 1.0 |
| 1657 | 2 | 2 | 1.0 |
| 1625 | 2 | 2 | 1.0 |
| 1658 | 2 | 2 | 1.0 |
| 1651 | 2 | 2 | 1.0 |
| 1247 | 1 | 1 | 1.0 |
| 1663 | 1 | 1 | 1.0 |
| 1654 | 1 | 1 | 1.0 |
| 640 | 1 | 1 | 1.0 |
| 620 | 1 | 1 | 1.0 |
| 1652 | 1 | 1 | 1.0 |
| 1628 | 1 | 1 | 1.0 |
| 1235 | 1 | 1 | 1.0 |
| 1630 | 1 | 1 | 1.0 |
| 1618 | 1 | 1 | 1.0 |
| 1662 | 1 | 1 | 1.0 |
| 3495 | 1 | 1 | 1.0 |
| 1605 | 1 | 1 | 1.0 |
| 1632 | 1 | 1 | 1.0 |
| 1550 | 1 | 1 | 1.0 |
| 1642 | 1 | 1 | 1.0 |
| 1646 | 1 | 1 | 1.0 |
| 1534 | 1 | 1 | 1.0 |
Showing the 30 best-supported peaks of 52 total for Protein random coil.
Spectrum logic
A functional-group assignment becomes more confident when several expected bands appear together. Use this page to find the strongest-supported peaks, then confirm that the same sample exhibits a coherent pattern rather than a single isolated hit.
Real-world usage
These pages are useful for unknown material analysis, peak explanation in reports, polymer troubleshooting, and verifying whether a candidate material family is chemically plausible.
Common mistakes
- Using one functional-group page as a complete material verdict without checking the rest of the spectrum.
- Assuming the strongest band is always the most diagnostic one.
- Forgetting that processing, additives, aging, and mixtures can shift or broaden expected peaks.
Verification advice
Use DSC, GC-MS, or TGA when several material families share similar bands or when mixture effects make the FTIR assignment uncertain.
Literature behind these assignments
-
1647 cm⁻¹ confidence 1.0
“Blood (A) can easily be distin- (O-H stretch), 3284.3 (H-bonded O-H stretch), 1646.9 cm)1 (amide I random coil), and 1558.8 (amines bend).”
Elkins - 2011 - Rapid Presumptive Fingerprinting of Body Fluids DOI: 10.1111/j.1556-4029.2011.01870.x -
1640 cm⁻¹ confidence 1.0
“Unstructured proteins and random coils display a symmetGaussian random site energies are sampled around a mean of cm-1 ∼1640 ric peak in the FTIR spectrum at that overlaps cm-1 cm-1 R ) (σ 1650 for the helix and random coil 10 and 12 R-heli”
Ganim 等 - 2008 - Amide I two-dimensional infrared Spectroscopy of p DOI: 10.1021/ar700188nCCC -
1656 cm⁻¹ confidence 1.0
“On the contrary, compared with absorption silka Random coil of 1656 1535 peak of BDO-extended PU, that of Dow BPU decreases in the silka”
Silkinspired polyurethane containing GlyAlaGlyAla tetrapeptide. II. physical properties and structure DOI: 10.1002/app.39185 -
1645 cm⁻¹ confidence 1.0
“As a rule of cm-1 weremechanicallymanipulatedinordertocharacterizetheintrafibrillar thumb, a peak near 1645 is indicative of random coil, cm-1 1620-1640cm-1 ofAβ25-35fibrils α-helix ofβ-sheet[24-27].”
Structural and nanomechanical comparison of epitaxially and solution-grown amyloid β25–35 fibrils DOI: 10.1016/j.bbapap.2015.01.003 -
1660 cm⁻¹ confidence 1.0
“Materials and methods occurring at 1645-1657 random coils and the cm(cid:1)1band a1660 to triple helix, with contribution from 2.1.”
Muyonga 等 - 2004 - Fourier transform infrared (FTIR) spectroscopic st DOI: 10.1016/j.foodchem.2003.09.038 -
3200 cm⁻¹ confidence 1.0
“LLM confirmed rule peak-group candidate”
Rozenberg 和 Shoham - 2007 - FTIR spectra of solid poly-L-lysine in the stretch DOI: 10.1016/j.bpc.2006.07.008 -
1643 cm⁻¹ confidence 1.0
“The random coil cm-1 conformation shows IR bands around 1643 and 1649 [19].”
Sadat 和 Joye - 2020 - Peak Fitting Applied to Fourier Transform Infrared DOI: 10.3390/app10175918 -
1651 cm⁻¹ confidence 1.0
“expense of random coils at 1645 A decrease in the band area cm(cid:1)1 of random coils also led to an increase in band area of 1651 associatedwitha-helices.Atanairvelocityof1.5m/sanincreasein”
Singh 等 - 2015 - Electrohydrodynamic drying (EHD) of wheat and its DOI: 10.1016/j.lwt.2015.06.051
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