Fast muscle myosin responds in similar way to F-actin and to phalloidin F-actin. It is activated 7.5 fold at infinite F-actin concentration and 6.8 fold at infinite phalloidin F-actin. The actomyosin dissociation constants are 0.89 +/- 0.34 microM with F-actin and 0.90 +/- 0.71 microM with phalloidin F-actin. Slow muscle myosin responds differently to F-actin and to phalloidin F-actin. It is activated 3.76 fold at infinite F-actin concentration and only 2.27 fold at infinite phalloidin F-actin concentration. The actomyosin dissociation constants are 1.95 +/- 1.27 microM with F-actin and 0.27 +/- 0.16 microM with phalloidin F-actin. At first glance this means that substitution of F-actin with phalloidin F-actin magnifies the difference between fast muscle and slow muscle myosins. Furthermore the change of the dissociation constants may affect the contractile force of the attached crossbridge.

Differential response of fast and slow myosin ATPase from skeletal muscle to F-actin and to phalloidin F-actin / G. Trombetta, R. Adami, O. Cintio, E. Grazi. - In: BIOCHIMICA ET BIOPHYSICA ACTA-GENERAL SUBJECTS. - ISSN 0304-4165. - 1569:1-3(2002 Jan 15), pp. 135-138.

Differential response of fast and slow myosin ATPase from skeletal muscle to F-actin and to phalloidin F-actin

R. Adami
Secondo
;
2002

Abstract

Fast muscle myosin responds in similar way to F-actin and to phalloidin F-actin. It is activated 7.5 fold at infinite F-actin concentration and 6.8 fold at infinite phalloidin F-actin. The actomyosin dissociation constants are 0.89 +/- 0.34 microM with F-actin and 0.90 +/- 0.71 microM with phalloidin F-actin. Slow muscle myosin responds differently to F-actin and to phalloidin F-actin. It is activated 3.76 fold at infinite F-actin concentration and only 2.27 fold at infinite phalloidin F-actin concentration. The actomyosin dissociation constants are 1.95 +/- 1.27 microM with F-actin and 0.27 +/- 0.16 microM with phalloidin F-actin. At first glance this means that substitution of F-actin with phalloidin F-actin magnifies the difference between fast muscle and slow muscle myosins. Furthermore the change of the dissociation constants may affect the contractile force of the attached crossbridge.
Fast; Phalloidin F-actin; Slow myosin
Settore BIO/09 - Fisiologia
Settore BIO/11 - Biologia Molecolare
Settore BIO/13 - Biologia Applicata
Settore BIO/10 - Biochimica
Settore BIO/17 - Istologia
Settore BIO/06 - Anatomia Comparata e Citologia
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/209348
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