A protein-bound polysaccharide from Basidiomycetes enhances myosin phosphorylation but inhibits myosin ATPase activity: studies with a crude actomyosin preparation of chicken gizzard smooth muscle.
Chicken gizzard actomyosin, containing the calmodulin-myosin light chain kinase (MLCK) system, was incubated in the presence of various concentrations of PSK, a protein-bound polysaccharide from Basidiomycetes, together with Ca2+ and Mg-ATP. The phosphorylation of myosin was enhanced half-maximally by 10-4 g/ml of PSK. However, a similar concentration of PSK reduced the Mg-ATPase activity of the actomyosin. The former was brought about through stimulation of the MLCK activity and the latter through inhibition of the myosin ATPase activity.
Kaneko
K
K
Department of Pharmacology, Gunma University School of Medicine.
Takano-Ohmuro
H
H
Iwai
T
T
Kohama
K
K
D000205:Actomyosin / Q000378:metabolism; D000818:Animals; D001487:Basidiomycota; D002645:Chickens; D066298:In Vitro Techniques; D007700:Kinetics; D009130:Muscle, Smooth / Q000378:metabolism; D009218:Myosins / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D010766:Phosphorylation; D011509:Proteoglycans / Q000494:pharmacology*
D011509:Proteoglycans; C010770:polysaccharide-K; D000205:Actomyosin; D009218:Myosins