The role of actin sulfhydryls in actin-myosin interaction.
Rabbit white skeletal and dog cardiac actins combined fully with the heavy meromyosins at 4 degrees C and low ionic strength (10.03); the complexes (actin-heavy meromyosin) were mostly in a heavy component which settled rapidly during rotor acceleration. Increasing the temperature to 24 degrees C favored formation of the heavy component while increasing the ionic strength to 10.3 decreased formation of the heavy component. Modification of actin with p-mercuribenzoate (PCMB) generally reduced the heavy component and viscosity but did not interfere with actin-heavy meromyosin combination. Modification with iodoacetamide or N-ethylmaleimide had similar effects. Addition of ATP reduced viscosity and eliminated the heavy component at levels which partially dissociated actin-heavy meromyosin. Modification of heavy meromyosin with PCMB inhibited combination with actin. The characteristics of interaction of the cardiac proteins varied less with temperature but more with ionic strength than those of skeletal proteins.
Heazlitt
R
R
Medical Research Section, Veterans Administration Hospital, Cardiac Research Laboratory and Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio 45220, USA.
Conway
G
G
Montag
J
J
D000199:Actins / Q000737:chemistry*; D000255:Adenosine Triphosphate / Q000737:chemistry; D000818:Animals; D001671:Biochemistry / Q000379:methods; D004285:Dogs; D007477:Ions; D009206:Myocardium / Q000378:metabolism; D015879:Myosin Subfragments / Q000737:chemistry; D009218:Myosins / Q000737:chemistry*; D011485:Protein Binding; D011817:Rabbits; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013696:Temperature; D014783:Viscosity; D020245:p-Chloromercuribenzoic Acid / Q000737:chemistry
D000199:Actins; D007477:Ions; D015879:Myosin Subfragments; D013438:Sulfhydryl Compounds; D020245:p-Chloromercuribenzoic Acid; D000255:Adenosine Triphosphate; D009218:Myosins