N-Terminal Region of Gizzard Myosin Heavy Chain Is Critical for the ATPase Activity1
- 1 July 1981
- journal article
- research article
- Published by Oxford University Press (OUP) in The Journal of Biochemistry
- Vol. 90 (3) , 833-842
- https://doi.org/10.1093/oxfordjournals.jbchem.a133540
Abstract
Two different HMM species of gizzard myosin were prepared under conditions such that the phosphorylation of light chain was fully maintained. They were different in the N-terminal structure of the heavy chain but not in the light chain composition. A significant decrease in the Mg2+-ATPase activity was observed in one class of HMM which was proteolytically cleaved intramolecularly at site 1, 5K daltons from the masked N terminus. Another class of HMM without the cleavage at site 1 showed ATPase activity similar to that of myosin. The decrease in ATPase activity was not caused by denaturation since similar amounts of initial burst of P1 liberation were observed with both HMMs and myosin. Kinetic and substructure analyses of HMM revealed that the activity change depended solely on the cleavage at site 1. The N-terminal region of gizzard myosin heavy chain may thus have an important role in maintaining the active site structure.Keywords
This publication has 3 references indexed in Scilit:
- Location of the Nonidentical Two Reactive Lysine Residues in the Myosin Molecule1The Journal of Biochemistry, 1981
- Photoaffinity labelling with an ATP analog of the N-terminal peptide of myosinBiochemical and Biophysical Research Communications, 1979
- Chymotryptic heavy meromyosin from gizzard myosin: A proteolytic fragment with the regulatory properties of the intact myosinBiochemical and Biophysical Research Communications, 1978