Lebherz H G
J Biol Chem. 1975 Aug 10;250(15):5976-81.
The quantitative and qualitative changes in fructose-P2 aldolase isoenzyme concentrations during development of "red" (leg) and "white" (breast) skeletal muscles of the chick were investigated. (a) The aldolase C to A subunit transition associated with muscle development is accompanied by large increases in aldolase activity (units/g, wet weight) and in specific catalytic activity (units/mg of protein). The accumulations in both muscle types follow pseudo-first order kinetics with doubling times of 2 to 3 days. The steady state level of aldolase activity in breast muscle (about 150 units/g) is approximately 4-fold higher than that in leg muscle (about 40 units/g). In contrast to leg muscle, the major increase in aldolase activity in breast muscle occurs during postembryonic development. (b) Immunotitration studies demonstrated a direct correlation between increases in enzyme activity and aldolase A subunits during postembryonic muscle development. It was calculated that under steady state conditions, aldolase A4 comprises about 1 percent and 0.26 percent, respectively, of the total wet weight of breast and leg muscle. (c) regulation at the level of protein synthesis in effecting the postembryonic accumulation of aldolase A4 in the muscle types was investigated in short term amino acid incorporation experiments. After a 1-hour pulse with [3H]leucine, aldolase from breast and leg muscle was isolated in a single step by affinity chromatography on phosphocellulose. Incorporation of tritum into aldolase A4 and into soluble or total protein was compared. Between 4 and 38 days after hatching, the rate of aldolase synthesis relative to the synthesis of soluble muscle protein increased about 7- and 3-fold, respectively, in breast and leg muscle. Relative to total protein, incorporation of [3H]leucine into A4 increased about 3-fold in breast muscle, and decreased slightly in leg muscle between 5 and 25 days after hatching. By 3 weeks after hatching, incorporation of [3H]leucine into aldolase A4 relative to incorporation into total protein was about 6-fold higher in breast muscle than it was in leg muscle. The present work, as well as other recent studies, are discussed in relation to the mechanism involved in controlling tissue-specific and stage-specific levels of aldolase isoenzymes in animal cells.
研究了雏鸡“红色”（腿部）和“白色”（胸部）骨骼肌发育过程中果糖 - P2醛缩酶同工酶浓度的定量和定性变化。（a）与肌肉发育相关的醛缩酶C向A亚基的转变伴随着醛缩酶活性（单位/克，湿重）和比催化活性（单位/毫克蛋白质）的大幅增加。两种肌肉类型中的积累均遵循假一级动力学，倍增时间为2至3天。胸肌中醛缩酶活性的稳态水平（约150单位/克）比腿肌（约40单位/克）高约4倍。与腿肌相反，胸肌中醛缩酶活性的主要增加发生在胚胎后发育期间。（b）免疫滴定研究表明，胚胎后肌肉发育过程中酶活性的增加与醛缩酶A亚基之间存在直接相关性。据计算，在稳态条件下，醛缩酶A4分别约占胸肌和腿肌总湿重的1%和0.26%。（c）在短期氨基酸掺入实验中研究了影响肌肉类型中醛缩酶A4胚胎后积累的蛋白质合成水平的调节。用[3H]亮氨酸脉冲1小时后，通过磷酸纤维素亲和色谱一步分离胸肌和腿肌中的醛缩酶。比较了氚掺入醛缩酶A4以及可溶性或总蛋白中的情况。在孵化后4至38天之间，胸肌和腿肌中醛缩酶合成速率相对于可溶性肌肉蛋白合成速率分别增加了约7倍和3倍。相对于总蛋白，[3H]亮氨酸掺入A4在胸肌中增加了约3倍，在孵化后5至25天之间腿肌中略有下降。到孵化后3周时，相对于掺入总蛋白，[3H]亮氨酸掺入胸肌中醛缩酶A4的量比腿肌高约6倍。结合动物细胞中醛缩酶同工酶组织特异性和阶段特异性水平控制机制，对本研究以及其他近期研究进行了讨论。
