Tentative assignment of the potato serine protease inhibitor group as β-II proteins based on their spectroscopic characteristics
article
Potato serine protease inhibitor (PSPI) is the most abundant protease inhibitor group in potato tuber. The investigated PSPI isoforms have a highly similar structure at both the secondary and the tertiary level. From the results described, PSPI is classified as a β-II protein based on (1) the presence in the near-UV spectra of sharp peaks, indicating a rigid and compact protein; (2) the sharp transition from the native to the unfolded state upon heating (only 6°C) monitored by a circular dichroism signal at 222 nm; and (3) the similarity in secondary structure to soybean trypsin inhibitor, a known β-II protein, as indicated by a similar far-UV CD spectrum and a similar amide I band in the IR spectrum. The conformation of PSPI was shown also to be stable at ambient temperature in the pH range 4-7.5. Upon lowering the pH to 3.0, some minor changes in the protein core occur, as observed from the increase of the intensity of the phenylalanine peak in the near-UV CD spectrum. Chemicals / CAS: Serine Proteinase Inhibitors
Topics
β-II proteinpH stabilityPSPIThermal unfoldingisoproteinserine proteinase inhibitorarticlecontrolled studyenvironmental temperatureheatingnonhumanpHpotatoprotein conformationprotein foldingprotein secondary structureprotein stabilityprotein tertiary structurethermostabilityultraviolet spectroscopyCalorimetry, Differential ScanningCircular DichroismDrug StabilityHeatProtein FoldingProtein Structure, SecondarySerine Proteinase InhibitorsSolanum tuberosumSpectrometry, FluorescenceSpectrophotometry, UltravioletGlycine maxSolanum tuberosum
TNO Identifier
238253
ISSN
00218561
Source
Journal of Agricultural and Food Chemistry, 52(25), pp. 7704-7710.
Pages
7704-7710
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