ADENOSINE TRIPHOSPHATE TRANSPHOSPHORYLASES

通过系统地合成和测量它们的平衡底物结合 包括镁的结合部位(A)的两组多肽 兔肌肉核苷酸底物(MgATP2-和MgADP1-)的螯合物 肌酸激酶和(B)未复合的核苷酸底物(ADP3-和Amp2-) 肌酸激酶，希望能从化学上概括和推导出肌酸激酶的要求。 底物与ATP-AMP转磷酸酶的结合。 为了提供有关ATP转磷酸化的基本过程的信息，a 全面的物理化学方法，其中将包括对其 一级结构，已经启动或将在几种酶上继续 它们共同具有催化磷酰基转移的能力 (或焦磷酰基)结合到合适的受体，但不同 在其底物专一性要求或要求范围方面明显 对于接受者来说。据推测，某些物理和化学物质 相似之处和显著的不同之处将在 对这些酶蛋白及其催化反应的详细研究，以便 最终，一幅宽泛的图景将浮出水面，这将允许人们定义更多 显然，转磷酸化的化学和物理要求也是如此 以允许对可被要求的个别要求进行描述 特异性起作用。为了达到这一目标，研究将包括 以下一系列酶：三磷酸腺苷-腺苷三磷酸转磷酸酶(腺苷酸激酶) 兔和小牛肌肉和肝脏的同工酶；核苷 三磷酸-核苷二磷酸转磷酸酶(核苷 来自酵母；来自酵母的ATP-肌酸转移酶同工酶 兔和小牛；猪脑中的三磷酸腺苷-硫胺素焦磷酸激酶。在这种情况下 对于最后一种酶，首先将尝试确保同质 制备并提供初步表征，物理上， 化学上和动力学上。

By systematic syntheses and measurements of their equilibrium substrate binding of two sets of peptides which encompass the binding sites (a) for the magnesium chelates of the nucleotide substrates (MgATP2- and MgADP1-) of rabbit muscle myokinase and (b) of the uncomplexed nucleotide substrates (ADP3- and AMP2-) of the myokinase, it is hoped to chemically outline and deduce the requirements of the binding of the substrates to ATP-AMP transphosphorylase. To provide information on the basic process of ATP-transphosphorylation, a comprehensive physico-chemical approach, which will include analyses of their primary structures, has been initiated or will be continued on several enzymes which have in common the ability to catalyze the transfer of a phosphoryl group (or pyrophosphoryl group) of ATP to a suitable acceptor, but which differ markedly in their substrate specificity requirements or range of requirements for the acceptor. It is presumed that certain physical and chemical similarities as well as significant differences will manifest themselves in detailed studies on these enzyme proteins and their catalyzed reactions, so that eventually a broad picture will emerge and which will permit one to define more clearly the chemical and physical requirements for transphosphorylation as well as to permit a delineation of individual requirements which may be demanded for the specificity functions. To this aim, the studies will encompass the following series of enzymes: ATP-AMP transphosphorylase (adenylate kinase) isoenzymes from the muscle and liver of rabbit and calf; nucleoside triphosphate-nucleoside diphosphate transphosphorylase (nucleoside diphosphokinase) from yeast; ATP-creatine transphophorylase isoenzymes from rabbit and calf; ATP-thiamine pyrophosphokinase from porcine brain. In the case of the last enzyme, attempts will be made first to secure a homogeneous preparation and to provide a preliminary characterization, physically, chemically and kinetically.