Possible presence of the difference peptide in alkali light chain 1 of fish fast skeletal myosin.
1. Presence of N-terminal peptide ("difference peptide") in alkali light chain 1 (A1) of fish fast skeletal myosin was examined by comparing two kinds of light chain-based myosin subfragment 1 (S1) isozymes from the yellowtail Seriola quinqueradiata. 2. On tryptic digestion, A1 was cleaved to a smaller fragment (mol. wt decrement by 2000) along with the cleavage of S1 heavy chain, while A2 was resistant to trypsin. Two-dimensional gel electrophoresis showed that A1 released a basic peptide by tryptic digestion. 3. Both S1 isozymes showed clear kinetic differences in actin-activated Mg-ATPase activity, suggesting a higher affinity of A1 for actin. Affinity of A2 for heavy chain was also estimated to be about 2-fold higher than that of A1, as judged by the model experiments in which rabbit S1 isozymes were hybridized with heterologous alkali light chains.
Ochiai
Y
Y
Laboratory of Marine Biochemistry, Faculty of Agriculture, University of Tokyo, Japan.
Kobayashi
T
T
Handa
A
A
Watabe
S
S
Hashimoto
K
K
D000199:Actins / Q000494:pharmacology; D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase / Q000378:metabolism; D002845:Chromatography; D005399:Fishes; D015151:Immunoblotting; D007527:Isoenzymes / Q000378:metabolism; D009132:Muscles / Q000737:chemistry*; D015879:Myosin Subfragments / Q000032:analysis*; D009218:Myosins / Q000378:metabolism; D010446:Peptide Fragments / Q000032:analysis*; D055503:Protein Multimerization; D011817:Rabbits; D014357:Trypsin
D000199:Actins; D007527:Isoenzymes; D015879:Myosin Subfragments; D010446:Peptide Fragments; D014357:Trypsin; D017301:Ca(2+) Mg(2+)-ATPase; D009218:Myosins