Claycomb W C
Biochem J. 1976 Feb 15;154(2):387-93. doi: 10.1042/bj1540387.
Poly(ADP-ribose) polymerase activity in nuclei isolated from differentiating cardiac muscle of the rat has been characterized and its activity measured during development. Optimum enzyme activity is observed at pH 8.5. Poly(ADP-ribose) polymerase is inhibited by ATP, thymidine, nicotinamide, theophylline, 3-isobutyl-1-methylxanthine and caffeine and stimulated by actinomycin D. The activity measured under optimal assay conditions increases during differentiation of cardiac muscle and is inversely related to the rate of DNA synthesis and to the activities of DNA polymerase alpha and thymidine kinase. When DNA synthesis and the activity of DNA polymerase alpha are inhibited in cardiac muscle of the 1-day-old neonatal rat by dibutyryl cyclic AMP or isoproterenol, the specific activity of poly(ADP-ribose) polymerase measured in isolated nuclei is increased. The concentration of NAD+ in cardiac muscle increases during postnatal development. In the adult compared with the 1-day-old neonatal rat the concentration of NAD+ relative to fresh tissue weight, DNA or protein increased 1.7-fold, 5.2-fold or 1.4-fold respectively. The concentration of NAD+ in cardiac muscle of the 1-day-old neonatal rat can be increased by approx. 20% by dibutyryl cyclic AMP. These data suggest that NAD+ and poly(ADP-ribose) polymerase may be involved with the repression of DNA synthesis and cell proliferation in differentiating cardiac muscle.
已对从大鼠分化心肌中分离出的细胞核中的聚（ADP - 核糖）聚合酶活性进行了表征，并在发育过程中测量了其活性。在pH 8.5时观察到最佳酶活性。聚（ADP - 核糖）聚合酶受到ATP、胸苷、烟酰胺、茶碱、3 - 异丁基 - 1 - 甲基黄嘌呤和咖啡因的抑制，并受到放线菌素D的刺激。在最佳测定条件下测得的活性在心肌分化过程中增加，并且与DNA合成速率以及DNA聚合酶α和胸苷激酶的活性呈负相关。当用二丁酰环磷酸腺苷或异丙肾上腺素抑制1日龄新生大鼠心肌中的DNA合成和DNA聚合酶α的活性时，在分离的细胞核中测得的聚（ADP - 核糖）聚合酶的比活性增加。心肌中NAD⁺的浓度在出生后发育过程中增加。与1日龄新生大鼠相比，成年大鼠心肌中相对于新鲜组织重量、DNA或蛋白质的NAD⁺浓度分别增加了1.7倍、5.2倍或1.4倍。1日龄新生大鼠心肌中NAD⁺的浓度可通过二丁酰环磷酸腺苷增加约20%。这些数据表明，NAD⁺和聚（ADP - 核糖）聚合酶可能参与了分化心肌中DNA合成和细胞增殖的抑制。
