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Using flash photolysis of caged ATP in skinned muscle fibers from rat psoas, we examined the inhibitory effects of 2,3-butanedione monoxime (BDM) on the contraction kinetics and the rate of ATP hydrolysis of the cross-bridges at approximately 10 degrees C. The hydrolysis rate was estimated from the stiffness records. The effects of BDM were compared with those of orthophosphate (P(i)) and of reduction in [Ca2+] (low Ca2+), and it was found that i) BDM and low Ca2+ inhibited ATPase activity to the same extent as they inhibited the steady tension, whereas P(i) inhibited ATPase activity much less than tension; ii) BDM and P(i) decreased tension per stiffness during the steady contraction more than did low Ca2+; iii) neither BDM nor low Ca2+ affected the initial relaxation of the fiber on release of ATP, but P(i) slightly slowed it; and iv) BDM hardly influenced the rate of contraction development after relaxation, although P(i) and low Ca2+ accelerated it. We concluded that BDM inhibits the Ca(2+)-regulated attachment of the cross-bridges and force-generation of the attached cross-bridges.
K Kagawa, and
K Horiuti, and
K Yamada
October 1997,
The Japanese journal of physiology,
K Kagawa, and
K Horiuti, and
K Yamada
January 1993,
Advances in experimental medicine and biology,
K Kagawa, and
K Horiuti, and
K Yamada
March 1995,
Biophysical journal,
K Kagawa, and
K Horiuti, and
K Yamada
January 2001,
Journal of muscle research and cell motility,
K Kagawa, and
K Horiuti, and
K Yamada
March 2015,
Cold Spring Harbor protocols,
K Kagawa, and
K Horiuti, and
K Yamada
September 1989,
Nature,
K Kagawa, and
K Horiuti, and
K Yamada
July 1993,
Biophysical journal,
K Kagawa, and
K Horiuti, and
K Yamada
November 1996,
Biophysical journal,
K Kagawa, and
K Horiuti, and
K Yamada
August 1990,
The Journal of physiology,
K Kagawa, and
K Horiuti, and
K Yamada
January 1991,
The Journal of physiology,
