Analysis of the multiple forms of the 20,000-dalton myosin light, chain from uterine arterial smooth muscles
2D gel electrophoresis resolved the light chain (LC) in four spots, three spots were phosphorylated. Phosphorylation was determined by densitometry (S) and (/sup 32/P)phosphate incorporation (P). Molar (/sup 32/P)phosphate incorporation was quantitated for each LC spot. Phosphorylation was low in resting or drug-relaxed muscles and high in contracting or stretched muscles. At low phosphorylation S > P, this discrepancy can be explained by the presence of unphosphorylated isoforms in the phosphorylated spots. Indeed, unphosphorylated uterine LC exhibited three spots on electrophoretograms (distribution: 0, 13, 7, 80%), whereas arterial LC showed two spots (0, 15, 0, 85%). At high phosphorylation P > S, this aberration is caused by diphosphorylation. In the intact tissue of uterus, the ratio of Thr-P to Ser-P, and the level of diphosphorylation are higher than in artery. The molecular weight and isoelectric points of uterine and arterial LC are the same, but the percentage distribution of the unphosphorylated isoforms, the molar phosphate incorporation in the phosphorylated spots, and the extent of diphosphorylation are different.
- Research Organization:
- Univ. of Illinois, Chicago
- OSTI ID:
- 6992006
- 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. 45:4; ISSN FEPRA
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
ARTERIES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BLOOD VESSELS
BODY
CARDIOVASCULAR SYSTEM
CHEMICAL REACTIONS
DAYS LIVING RADIOISOTOPES
ELECTROPHORESIS
FEMALE GENITALS
GLOBULINS
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
MOLECULAR WEIGHT
MUSCLES
MYOSIN
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANS
OXYGEN COMPOUNDS
PHOSPHATES
PHOSPHORUS 32
PHOSPHORUS COMPOUNDS
PHOSPHORUS ISOTOPES
PHOSPHORYLATION
PROTEINS
RADIOISOTOPES
TRACER TECHNIQUES
UTERUS