Phosphorylation of human skeletal muscle myosin
Phosphorylation of the P-light chains (phosphorylatable light chains) in human skeletal muscle myosin was studied in vitro and in vivo under resting an d contracted conditions. biopsy samples from rested vastus lateralis muscle of male and female subjects were incubated in oxygenated physiological solution at 30/sup 0/C. Samples frozen following a quiescent period showed the presence of only unphosphorylated P-light chains designated LC2f (light chain two of fast myosin) CL2s and LC2s'(light chains two of slow myosin). Treatment with caffeine (10 mM) or direct electrical stimulation resulted in the appearance of three additional bands which were identified as the phosphorylated forms of the P-light chains i.e. LC2f-P, LC2s-P and LC2s'-P. The presence of phosphate was confirmed by prior incubation with (/sup 30/P) orthophosphate. Muscle samples rapidly frozen from resting vastus lateralis muscle revealed the presence of unphosphorylated and phosphorylated P-light chains in approximately equal ratios. Muscle samples rapidly frozen following a maximal 10 second isometric contraction showed virtually only phosphorylated fast and slow P-light chains. These results reveal that the P-light chains in human fast and slow myosin may be rapidly phosphorylated, but the basal level of phosphorylation in rested human muscle considerably exceeds that observed in animal muscles studied in vitro or in situ.
- Research Organization:
- Univ. of Waterloo, Ontario
- OSTI ID:
- 5418004
- Report Number(s):
- CONF-8604222-
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Vol. 45:3; ISSN FEPRA
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
ANALEPTICS
ANIMALS
AROMATICS
AZAARENES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOPSY
CAFFEINE
CENTRAL NERVOUS SYSTEM AGENTS
CHEMICAL REACTIONS
DAYS LIVING RADIOISOTOPES
DIAGNOSTIC TECHNIQUES
DRUGS
GLOBULINS
HETEROCYCLIC COMPOUNDS
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
MAMMALS
MAN
MUSCLES
MYOSIN
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
OXYGEN COMPOUNDS
PHOSPHATES
PHOSPHORUS 32
PHOSPHORUS COMPOUNDS
PHOSPHORUS ISOTOPES
PHOSPHORYLATION
PRIMATES
PROTEINS
PURINES
RADIOISOTOPES
TRACER TECHNIQUES
VERTEBRATES
XANTHINES