Purification and characterization of a novel isoform of myosinase from spear squid liver.
A novel isoform of myosinase was purified to homogeneity from liver of spear squid by sequential chromatographies using SP Sephadex, hydroxylapatite, Zn/Co chelating affinity, and TSK-gel G2000SW columns. Myosinase activity was detected as a single peak of 45-kDa protein by gel filtration. The novel isoform of myosinase specifically hydrolyzed a rabbit skeletal muscle myosin heavy chain into products of 120 and 100 kDa in the presence of Co(2+) ions, and the cleavage site in the myosin heavy chain was quite different from those of two known myosinase isoforms, I and II. Therefore, we named the novel isoform myosinase III. Myosinase III was also distinguishable from myosinase I by its amino-terminal sequence. The sequence showed similarity to an internal sequence of the astacin family.
Tamori
J
J
Department of Chemistry, Faculty of Science and Technology, Sophia University, Tokyo, 102-8554, Japan.
Kanzawa
N
N
Tajima
T
T
Tamiya
T
T
Tsuchiya
T
T
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D049832:Decapodiformes / Q000201:enzymology* / Q000235:genetics; D066298:In Vitro Techniques; D007527:Isoenzymes / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D008099:Liver / Q000201:enzymology*; D008666:Metalloendopeptidases / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D008969:Molecular Sequence Data; D018995:Myosin Heavy Chains / Q000737:chemistry / Q000378:metabolism; D011817:Rabbits; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
D007527:Isoenzymes; D008666:Metalloendopeptidases; C079297:myosinase I; C079298:myosinase II; D018995:Myosin Heavy Chains