Abstract
Reactivity of amino groups of chromatographically homogenious β-trypsin was studied by chemical modification. Guanidination by 1-amidinyl-3, 5-dimethyl pyrazole nitrate led to modification of 10 out of 14 lysyl residues per molecule of trypsin. The guanidinating reagent was found to be a competitive inhibitor of trypsin. Extent of acetamidination by methyl acetimidate hydrochloride was affected by pH, temperature and the presence of various competitive inhibitors. All 14 ϵ-amino groups of lysyl residues could be acetamidinated in the presence of the competitive inhibitors at pH 9.5 and 25° without loss of enzyme activity. When 11 or more lysyl residues are modified by acetamidination, the enzyme is stable against autolysis in the absence of Ca ++. The enzyme with 10 of its 14 lysyl residues guanidinated loses its enzyme activity by autolysis at neutral pH at a rate comparable with unmodified enzyme.
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: Biochemical and Biophysical Research Communications
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.
