Journal
JOURNAL OF MUSCLE RESEARCH AND CELL MOTILITY
Volume 29, Issue 2-5, Pages 101-107Publisher
SPRINGER
DOI: 10.1007/s10974-008-9143-z
Keywords
Tropomyosin; Phosphorylation; Fish muscle
Categories
Ask authors/readers for more resources
Shark skeletal muscle tropomyosin is classified as an alpha-type isoform. The chemical structure is characterised by the absence of cysteine and the presence of a sub-stoichiometric amount of covalently bound phosphate. The protein migrates as a single component on a SDS polyacrylamide gel but is resolved into two components by chromatography and electrophoresis both in the presence of urea at mild alkaline pH. The only detectable difference between these components is the presence of phosphoserine in the tropomyosin form of greater net negative charge. Low ionic strength (pH 7) solutions of phosphorylated shark tropomyosin display significantly higher specific viscosity than unphosphorylated, consistent with the presence of a phosphorylation site within the overlap region, serine 283, as well as conservation of the positively charged amino terminal region. Similar observations were made with tropomyosin prepared from the trunk muscle of Atlantic cod. In a steady-state MgATPase assay, thin filaments (Ca2+) reconstituted with shark phosphorylated tropomyosin activate myosin to a greater extent than those composed of unphosphorylated. The difference is attributable chiefly to a change in V-max. Skeletal muscle tropomyosin is concluded to be phosphorylated in cartilaginous fishes as well as some teleosts.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available