Abstract
Fourier transform infrared spectroscopy was used to examine the effect of calcium binding on the secondary structure of two inhibited bovine β-trypsins. Neither the diisopropyl fluorophosphate- nor benzamidine-inhibited forms showed detectable secondary structure perturbation upon calcium binding at pD 6.9 and 5.0, respectively. Considered in light of the recent assignment of an amide I′ band to the autolysis loop of bovine β-trypsin, these results contradict the generally held hypothesis that calcium slows trypsin autolysis by induction of a conformational change at this site and support the recent contention that the mechanism of action has a specific electrostatic origin. In addition, the appearance of a band at 1699 cm −1 in the benzamidine-inhibited form can be interpreted as resulting from the NCN stretching vibrations of the amidinium moiety, which the observed crystal structure indicates is hydrogen-bonded to the carboxyl group of active-sie Asp-189.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Biochimica et Biophysica Acta (BBA)/Protein Structure and Molecular Enzymology
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
