Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.6.4.1 (myosin ATPase)
 1,140 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of an affinity modifier of myosin ATPase representing a mixed anhydride of AMP and mesitylene carboxylic acid (AMP-MA) on myosin with protected active centers was studied. The protection of active centers was performed by the method of Wells et al. Which consists in the stabilization of the myosin-MgADP complex in the enzyme active center by way of cross-linking of the active center with a Co-phenanthroline complex simultaneously interacting with two SH-groups of the protein. Myosin with protected active center completely loses its ability to hydrolyze ATP; however, it can be reactivated by way of SH-group reduction with a subsequent MgADP release from the active centers. Treatment of myosin with protected active centers with AMP-MA does not result in the reduction of the enzyme activity after removal of the Co-phenanthroline complex. This suggests that the irreversible inhibition of myosin ATPase by AMP-MA occurs due to the protein modification outside the active center(s), which provides support for our earlier made conclusion concerning the existence of an additional (with respect to active centers) substrate-binding site in the myosin molecule.
 ...
PMID:[Affinity modification of myosin with protected active centers: confirmation of the existence of an allosteric substrate-binding segment]. 253 15

Using mixed anhydride of AMP and mesitylene carboxylic acid carrying a fluorescent or radioactive label, it was found that the previously established irreversible inhibition of myosin ATPase is a result of protein covalent binding to the nucleotide residue of the inhibitor. The stoichiometry of the affinity labelling of heavy meromyosin is 1 mole of nucleotide residue of mixed anhydride per 1 mole of protein, that of subfragment 1-0.5 mole per 1 mole of protein. The lack of irreversible inhibition of the ATPase activity of subfragment 1 is suggestive of an existence of a regulatory substrate-binding site in the myosin molecule.
 ...
PMID:[Affinity modification of heavy meromyosin and subfragment 1 by mixed anhydrides of [14C] AMP, epsilon AMP and mesitylene carboxylic acid]. 621 86