Abstract
Chemical modification of arginine in malate dehydrogenases from pig heart mitochondria and from Bacillus subtilis was done using 4-hydroxy-3-nitrophenylglyoxal. Incorporation of 2 reagent molecules per subunit was observed concomitantly with complete loss of enzymatic activity. Partial protection was obtained with a substrate analogue and by formation of abortive ternary complexes, whereas coenzyme alone did not inhibit the inactivation. Modified inactive enzymes formed binary complexes with coenzyme as well as the ternary complex with NAD/sulfite. The substrate analogue 8-hydroxy-1,3,6-pyrenetrisulfonate was bound with reduced affinity, however. Because of the known stoichiometry of two reagent molecules per arginine we conclude that one arginine essential for substrate binding was modified in both enzymes.
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 callDisclaimer: 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.
