Binding of gizzard smooth muscle myosin subfragment-1 to actin in the presence and absence of adenosine 5'-triphosphate

Biochemistry ◽  
1983 ◽  
Vol 22 (3) ◽  
pp. 530-535 ◽  
Author(s):  
Lois E. Greene ◽  
James R. Sellers ◽  
Evan Eisenberg ◽  
Robert S. Adelstein
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Myosin ◽  
Myosin Subfragment ◽  
Myosin Subfragment 1 ◽  
Presence And Absence ◽  
Muscle Myosin

Interaction between the heavy and the regulatory light chains in smooth muscle myosin subfragment 1

Biochemistry ◽  
1992 ◽  
Vol 31 (4) ◽  
pp. 1201-1210 ◽  
Author(s):  
Hirofumi Onishi ◽  
Tetsuo Maita ◽  
Genji Matsuda ◽  
Keigi Fujiwara
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Myosin ◽  
Light Chains ◽  
Regulatory Light Chains ◽  
Myosin Subfragment ◽  
Myosin Subfragment 1 ◽  
Muscle Myosin

ADP release from myosin in permeabilized smooth muscle

1989 ◽  
Vol 256 (1) ◽  
pp. C59-C66 ◽  
Author(s):  
T. M. Butler ◽  
D. S. Pacifico ◽  
M. J. Siegman
Keyword(s):  
Smooth Muscle ◽  
Light Chains ◽  
Myosin Light Chains ◽  
Myosin Subfragment ◽  
Myosin Subfragment 1 ◽  
Adp Release ◽  
The Difference ◽  
Portal Veins ◽  
Cross Bridges ◽  
Muscle Myosin

The purpose of this study was to determine the nucleotide bound to myosin and its rate of release under relaxed and activated conditions in permeabilized rabbit portal veins. Incubation of the muscles in a relaxing solution containing [3H]-ATP resulted in the formation of 60-70 microM radiolabeled ADP in the muscle whether or not the myosin light chains had been thiophosphorylated. This value was similar to the estimate of the concentration of myosin subfragment 1. Upon transfer of the muscles to a chase solution containing no labeled ATP, there was a very slow loss of labeled ADP when the light chains were unphosphorylated, but a much faster release occurred when the light chains were thiophosphorylated. The results suggest that smooth muscle myosin exists primarily in a complex with ADP under both relaxed and phosphorylated conditions and that phosphorylation of all of the light chains results in a large increase in the rate of release of the products of ATP splitting from all of the myosin. Interestingly, the exponential release of ADP in relaxed muscle shows two components, one of which contains about two-thirds of the total ADP and is 5- to 10-fold faster than the other. If the difference in rates of ADP release observed in relaxed muscle persists when the myosin is phosphorylated, then it is possible that there is a 5- to 10-fold difference in rates of cycling for different phosphorylated cross bridges in smooth muscle.

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