Cole R P, Sukanek P C, Wittenberg J B, Wittenberg B A
J Appl Physiol Respir Environ Exerc Physiol. 1982 Nov;53(5):1116-24. doi: 10.1152/jappl.1982.53.5.1116.
The effect of myoglobin on oxygen consumption and ATP production by isolated rat skeletal muscle mitochondria was studied under steady-state conditions of oxygen supply. A method is presented for the determination of steady-state oxygen consumption in the presence of oxygen-binding proteins. Oxygen consumed in suspensions of mitochondria was replenished continuously by transfer from a flowing gas phase. Liquid-phase oxygen pressure was measured with an oxygen electrode; the gas-phase oxygen concentration was held constant at a series of fixed values. Oxygen consumption was determined from the characteristic response time of the system and the difference in the steady-state gas- and liquid-phase oxygen concentrations. ATP production was determined from the generation of glucose 6-phosphate in the presence of hexokinase. During steady-state mitochondrial oxygen consumption, the oxygen pressure in the liquid phase is enhanced when myoglobin is present. Functional myoglobin present in the solution had no effect on the relation of mitochondrial respiration and ATP production to liquid-phase oxygen pressure. Myoglobin functions in this system to enhance the flux of oxygen into the myoglobin-containing phase. Myoglobin may function in a similar fashion in muscle by increasing oxygen flux into myocytes.
在氧气供应的稳态条件下，研究了肌红蛋白对分离的大鼠骨骼肌线粒体耗氧量和ATP生成的影响。本文介绍了一种在存在氧结合蛋白的情况下测定稳态耗氧量的方法。线粒体悬浮液中消耗的氧气通过从流动气相转移而持续补充。用氧电极测量液相氧压；气相氧浓度保持在一系列固定值不变。根据系统的特征响应时间以及稳态气相和液相氧浓度的差异来确定耗氧量。在己糖激酶存在的情况下，根据6-磷酸葡萄糖的生成来确定ATP生成量。在稳态线粒体耗氧过程中，存在肌红蛋白时液相中的氧压会升高。溶液中存在的功能性肌红蛋白对线粒体呼吸和ATP生成与液相氧压之间的关系没有影响。在该系统中，肌红蛋白的作用是增加氧气向含肌红蛋白相的通量。肌红蛋白在肌肉中可能以类似方式发挥作用，即增加氧气向肌细胞的通量。
