Comparative Study of Respiration Kinetics and Protein Composition of Skinned Fibers from Various Types of Rat Muscle

S. G. Voloshchuk^1*, Yu. O. Belikova², T. P. Klyushnik¹, D. S. Benevolensky², and V. A. Saks³

¹Laboratory of Molecular Biochemistry, Center of Mental Health, Russian Academy of Medical Sciences, Zagorodnoe shosse 2, korpus 2, Moscow, 113152 Russia; fax: (095) 952-8940; E-mail: ktp@rcmh.msk.ru

²Laboratory of Biomembranes, Cardiology Research Center, ul. 3-ya Cherepkovskaya 15a, Moscow, 121552 Russia; fax: (095) 414-6699

³Laboratory of Bioenergetics, Institute of Chemical and Biological Physics, Tallinn, Estonia; fax: (014) 639-8313

^* To whom correspondence should be addressed.

Received March 24, 1997; Revision received July 29, 1997

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The respiration parameters of mitochondria from rat heart muscle and from fast-twitch and slow-twitch skeletal muscle skinned fibers were comparatively analyzed. Electrophoretic patterns of fiber protein composition were also compared. It was found that fibers with low affinity of mitochondria for ADP (i.e., heart and slow-twitch skeletal muscle soleus) contain a 27.5-kD protein that is absent from the fibers that exert high affinity for ADP (i.e., fast-twitch skeletal muscle gastrocnemius). Partial proteolysis, which increases the affinity of mitochondria of the heart and slow-twitch skeletal muscles for ADP, results in the disappearance of this protein. The results suggest that this protein may be an intracellular factor that controls the permeability of the outer mitochondrial membrane for ADP.

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KEY WORDS: heart, skeletal muscle, regulation of respiration, proteins, electrophoresis

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