Myofibrillar ATPase activity and mechanical performance of skinned fibres from rabbit psoas muscle.
Myofibrillar ATPase activity and mechanical performance of skinned fibres from rabbit psoas muscle.
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兔腰肌皮纤维的肌原纤维 ATP 酶活性和机械性能。
DOI：
10.1113/jphysiol.1994.sp020023
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
G. Elzinga
中科院分区：
文献类型：
--
作者：
E. Potma;G. Stienen;J. P. Barends;G. Elzinga
1.在15℃、pH=7.1、含5 mm、1 mm、离子强度200 mm、肌节长度2.4微米、等长收缩和重复长度变化的条件下，通过测力产生和肌原纤维ATP周转率，研究了化学剥皮兔腰大肌单纤维的能量周转率与力学性能的关系。通过在340 nm处的近紫外光的吸收，用光度计量学的方法测量了NADH的分解。2.在不同波幅(占纤维长度的1-10%)和不同频率(2.5-167赫兹)的方波变化过程中，测定力和ATPase活性。长度变化过程中的平均力值小于等长值，且随振幅和频率的增加而减小。在完全激活时(PCA 4.5)，等长ATP周转率(+/-S.E.M.)每头肌球蛋白为2.30±0.05S-1。ATP周转率随波幅和频率的增加而单调增加，直至达到饱和。观测到的最大增幅是等轴测值的2.4倍。3.在坡道缩短和快速伸展时，还测定了力和ATPase活性。平均受力随缩短速度的增加呈双曲线下降。当坡道速度达到0.5L~(-0)·S~(-1)时，三磷酸腺苷的周转率增加，而在较大速度时几乎保持不变(约为等长值的2.2倍)。4.等长力和ATPase活性均随钙浓度的降低而降低。它们在低钙浓度下没有比例变化，但这在很大程度上可以解释为残存的、钙(2+)依赖的、膜结合的ATPase的存在。在高钙浓度下，方波变化期间的ATPase活性高于等长值，但在低钙浓度(PCA>；6.1)下，长度变化期间的ATPase活性下降到等长值以下，最小达到等长值的40%。5.在长度变化过程中获得的ATPase活性和平均力量显示出高度的、运动方案无关的相关性。在长度变化中，ATP周转率除以平均力量水平(张力成本)大于等长张力成本。在23赫兹时，长度变化10%时的最大值是等长条件下拉伸成本的17倍。
1. The relationship between energy turnover and mechanical performance was investigated in chemically skinned single fibres from rabbit psoas muscle at 15 degrees C, pH = 7.1, with MgATP, 5 mM; free Mg2+, 1 mM; ionic strength, 200 mM and sarcomere length, 2.4 microns by measuring force production and myofibrillar ATP turnover during isometric contractions as well as during repetitive changes in length. ATP hydrolysis was stoichiometrically coupled to the breakdown of NADH, which was measured photometrically via the absorption of near UV light at 340 nm. 2. Force and ATPase activity were measured during square‐wave length changes of different amplitudes (1‐10% of the fibre length, Lo) and different frequencies (2.5‐167 Hz). The average force during the length changes was less than the isometric value and decreased with increasing amplitude and frequency. At full activation (pCa 4.5), the isometric ATP turnover rate (+/‐ S.E.M.) was 2.30 +/‐ 0.05 s‐1 per myosin head. ATP turnover increased monotonically with increasing amplitude as well as with increasing frequency until saturation was reached. The greatest increase observed was 2.4 times the isometric value. 3. Force and ATPase activity were also determined for ramp shortenings followed by fast restretches. The average force decreased with increasing shortening velocity in a hyperbolic fashion. The ATP turnover increased with ramp velocity up to 0.5 L0 s‐1 and stayed almost constant (at 2.2 times the isometric value) for larger velocities. 4. Isometric force and ATPase activity both decreased as the calcium concentration was decreased. They did not vary in proportion at low Ca2+ concentrations, but this could largely be accounted for by the presence of a residual, Ca(2+)‐dependent, membrane‐bound ATPase. At high calcium concentrations ATPase activity during square‐wave length changes was higher than the isometric value, but at low calcium concentrations (pCa > 6.1), the ATPase activity during the length changes decreased below the isometric value and reached a minimum of 40% of the isometric level. 5. ATPase activity and average force obtained during changes in length show a high, movement protocol‐independent correlation. During the length changes the rate of ATP turnover divided by the average force level (tension cost) was larger than the isometric tension cost. The largest value found, for 10% length changes at 23 Hz, was 17 times the tension cost under isometric conditions.(ABSTRACT TRUNCATED AT 400 WORDS)
DOI：
10.1073/pnas.82.3.658
发表时间：
1985-01-01
影响因子：
11.1
作者：
SIEMANKOWSKI, RF;WISEMAN, MO;WHITE, HD
通讯作者：
WHITE, HD
Ca2 对骨骼肌磷酸盐释放动力学的影响。
DOI：
--
发表时间：
1992
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Walker,JW;Lu,Z;Moss,RL
通讯作者：
Moss,RL
磷酸盐和钙对甘油兔骨骼肌纤维产生力的影响。
DOI：
--
发表时间：
1990
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Millar,NC;Homsher,E
通讯作者：
Homsher,E