Thiol groups of gizzard myosin heavy chains

Conference · Thu May 01 04:00:00 EDT 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:6905001

Bailin, G

Proteolysis of phosphorylated and /sup 3/H-labeled dinitrophenylated chicken gizzard myosin with trypsin released major fragments of M/sub r/ 25,000, 50,000 and 66,000 in a 1:1 ratio. They contained 57% of the dinitrophenyl (N/sub 2/ph) group bound to thiols of the heavy chains; 28% of the label was bound to the light chains. The fragments of M/sub r/ 25,000 and M/sub r/ 66,000 were dinitrophenylated predominantly when the K/sup +/-ATPase activity was inhibited. Thiolysis of phosphorylated and dinitrophenylated myosin with 2-mercaptoethanol removed 60% and 25% of the N/sub 2/ph group from the N-terminal and M/sub r/ 66,000 fragments of the heavy chain, respectively, when 48% of the K/sup +/-ATPase activity was restored. Papain proteolysis of the tryptic digest of modified myosin released a C-terminal segment from the fragment of M/sub r/ 66,000 and it contained most of the remaining label. Proteolysis of /sup 3/H-labeled dinitrophenylated myosin alone resulted in the same digestion pattern but less of the label was bound to the heavy chain fragments. In this case, restoration of enzymic activity occurred in thiolyzed dinitrophenylated myosin when the N/sub 2/ph group was removed from the light chains, predominantly. Conformational changes in gizzard myosin, mediated by phosphorylation, altered the reactivity of the thiols in specific fragments of the heavy chain. Thiol groups of the N- and C-terminal heavy chain regions are involved in maintaining the ATPase activity of myosin.

• Research Organization: UMDNJ-School of Osteopathic Medicine, Piscataway
• OSTI ID: 6905001
• Report Number(s): CONF-8606151-
• Conference Information: Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 45:6
• Country of Publication: United States
• Language: English

Related Subjects

550201 -- Biochemistry-- Tracer Techniques
560300* -- Chemicals Metabolism & Toxicology
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ACID ANHYDRASES
AROMATICS
ATP-ASE
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL EFFECTS
BODY
CHEMICAL REACTIONS
DECOMPOSITION
DIGESTIVE SYSTEM
DINITROPHENOL
ENZYME ACTIVITY
ENZYMES
GASTROINTESTINAL TRACT
GLOBULINS
HYDROLASES
HYDROXY COMPOUNDS
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
MYOSIN
NITRO COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC SULFUR COMPOUNDS
ORGANS
PHENOLS
PHOSPHOHYDROLASES
PROTEINS
PROTEOLYSIS
REACTION KINETICS
STOMACH
STRUCTURE-ACTIVITY RELATIONSHIPS
THIOLS
TRACER TECHNIQUES
TRITIUM COMPOUNDS