scholarly journals The scaling of myofibrillar actomyosin ATPase activity in apid bee flight muscle in relation to hovering flight energetics

2010 ◽  
Vol 213 (7) ◽  
pp. 1195-1206 ◽  
Author(s):  
G. N. Askew ◽  
R. T. Tregear ◽  
C. P. Ellington
Keyword(s):  
Atpase Activity ◽  
Flight Muscle ◽  
Hovering Flight ◽  
Actomyosin Atpase ◽  
Flight Energetics

Inhibition of muscle actomyosin ATPase activity by mitochondrial ATPase inhibitor

1977 ◽  
Vol 75 (4) ◽  
pp. 1104-1110 ◽  
Author(s):  
Shojiro Yamazaki ◽  
Hiroshi Hasebe ◽  
Haruhiko Takisawa ◽  
Yutaka Tamaura ◽  
Yuji Inada
Keyword(s):  
Atpase Activity ◽  
Mitochondrial Atpase ◽  
Atpase Inhibitor ◽  
Actomyosin Atpase

scholarly journals Calcium-Dependent Myosin from Insect Flight Muscles

1974 ◽  
Vol 63 (5) ◽  
pp. 553-563 ◽  
Author(s):  
William Lehman ◽  
Belinda Bullard ◽  
Kathleen Hammond
Keyword(s):  
Atpase Activity ◽  
Insect Flight ◽  
Calcium Regulation ◽  
Regulatory Proteins ◽  
Myosin Molecule ◽  
Thin Filaments ◽  
Actomyosin Atpase ◽  
Calcium Dependent ◽  
Regulatory Systems ◽  
Flight Muscles

Calcium regulation of the insect actomyosin ATPase is associated with the thin filaments as in vertebrate muscles, and also with the myosin molecule as in mollusks. This dual regulation is demonstrated using combinations of locust thin filaments with rabbit myosin and locust myosin with rabbit actin; in each case the ATPase of the hybrid actomyosin is calcium dependent. The two regulatory systems are synergistic, the calcium dependency of the locust actomyosin ATPase being at least 10 times that of the hybrid actomyosins described above. Likewise Lethocerus myosin also contains regulatory proteins. The ATPase activity of Lethocerus myosin is labile and is stabilized by the presence of rabbit actin. Tropomyosin activates the ATPase of insect actomyosin and the activation occurs irrespective of whether the myosin is calcium dependent or rendered independent of calcium.

Skeletal muscle force and actomyosin ATPase activity reduced by nitric oxide donor

1997 ◽  
Vol 83 (4) ◽  
pp. 1326-1332 ◽  
Author(s):  
William J. Perkins ◽  
Young-Soo Han ◽  
Gary C. Sieck
Keyword(s):  
Nitric Oxide ◽  
Mechanical Properties ◽  
Atpase Activity ◽  
Muscle Force ◽  
Isometric Force ◽  
Nitric Oxide Donor ◽  
No Donor ◽  
Single Fibers ◽  
Actomyosin Atpase ◽  
Cross Bridge

Perkins, William J., Young-Soo Han, and Gary C. Sieck.Skeletal muscle force and actomyosin ATPase activity reduced by nitric oxide donor. J. Appl. Physiol.83(4): 1326–1332, 1997.—Nitric oxide (NO) may exert direct effects on actin-myosin cross-bridge cycling by modulating critical thiols on the myosin head. In the present study, the effects of the NO donor sodium nitroprusside (SNP; 100 μM to 10 mM) on mechanical properties and actomyosin adenosinetriphosphatase (ATPase) activity of single permeabilized muscle fibers from the rabbit psoas muscle were determined. The effects of N-ethylmaleimide (NEM; 5–250 μM), a thiol-specific alkylating reagent, on mechanical properties of single fibers were also evaluated. Both NEM (≥25 μM) and SNP (≥1 mM) significantly inhibited isometric force and actomyosin ATPase activity. The unloaded shortening velocity of SNP-treated single fibers was decreased, but to a lesser extent, suggesting that SNP effects on isometric force and actomyosin ATPase were largely due to decreased cross-bridge recruitment. The calcium sensitivity of SNP-treated single fibers was also decreased. The effects of SNP, but not NEM, on force and actomyosin ATPase activity were reversed by treatment with 10 mMdl-dithiothreitol, a thiol-reducing agent. We conclude that the NO donor SNP inhibits contractile function caused by reversible oxidation of contractile protein thiols.

scholarly journals Functional interrelationship between calponin and caldesmon

1991 ◽  
Vol 280 (1) ◽  
pp. 33-38 ◽  
Author(s):  
R Makuch ◽  
K Birukov ◽  
V Shirinsky ◽  
R Dabrowska
Keyword(s):  
Skeletal Muscle ◽  
Smooth Muscle ◽  
Atpase Activity ◽  
Smooth Muscle Contraction ◽  
The Other ◽  
High Concentration ◽  
Thin Filaments ◽  
Actomyosin Atpase ◽  
Molar Excess ◽  
Low Concentrations

Calponin and caldesmon, constituents of smooth-muscle thin filaments, are considered to be potential modulators of smooth-muscle contraction. Both of them interact with actin and inhibit ATPase activity of smooth- and skeletal-muscle actomyosin. Here we show that calponin and caldesmon could bind simultaneously to F-actin when used in subsaturating amounts, whereas each one used in excess caused displacement of the other from the complex with F-actin. Calponin was more effective than caldesmon in this competition: when F-actin was saturated with calponin the binding of caldesmon was eliminated almost completely, whereas even at high molar excess of caldesmon one-third of calponin (relative to the saturation level) always remained bound to actin. The inhibitory effects of low concentrations of calponin and caldesmon on skeletal-muscle actomyosin ATPase were additive, whereas the maximum inhibition of the ATPase attained at high concentration of each of them was practically unaffected by the other one. These data suggest that calponin and caldesmon cannot operate on the same thin filaments. CA(2+)-calmodulin competed with actin for calponin binding, and at high molar excess dissociated the calponin-actin complex and reversed the calponin-induced inhibition of actomyosin ATPase activity.

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