RESUMO
Considerable stability of beta beta- (muscular) and gamma gamma- (neurospecific) forms to the denaturing influence of neutral salts of alkali metals is shown on purified isoenzymes (alpha alpha-, beta beta-, gamma gamma-forms) of beef brain and rabbit muscle. The rate of influence of these salts on the enzymic activity of the mentioned isoenzymes corresponds to the "lyotropic" series. Km of alpha alpha- and gamma gamma-isoenzymes are determined for 2-phosphoglycerate and phosphoenolpyruvate. It is found that alpha alpha-isoenzyme has larger affinity to phosphoenolpyruvate than gamma gamma-isoenzyme and it appears to play an essential role in participation of the given isoenzymes in the glycolysis and glyconeogenesis processes.
Assuntos
Encéfalo/enzimologia , Isoenzimas/análise , Fosfopiruvato Hidratase/análise , Animais , Bovinos , Técnicas In Vitro , Cinética , Metais/farmacologia , Músculos/enzimologia , Neuroglia/análise , Neurônios/enzimologia , CoelhosRESUMO
It is established that GABA interacts with tyrosine hydroxylase through the allosteric site which is not identical to sites of tyrosine, DOPA, pterin cofactor, dopamine binding. This interaction is very significant in the GABA influence on the regulation of the tyrosine hydroxylase activity by presynaptic receptors. GABA is supposed to be able to cause dissociation of oligomeric forms of tyrosine hydroxylase.
Assuntos
Hipotálamo/enzimologia , Tirosina 3-Mono-Oxigenase/metabolismo , Ácido gama-Aminobutírico/metabolismo , Regulação Alostérica , Animais , RatosRESUMO
Neuron-specific enolase and phosphoglycerate mutase with specific activities of 106 and 215 U/mg, respectively, have been purified from human brain. Hydrophobic chromatography for enolase and blue Sepharose affinity chromatography for phosphoglycerate mutase were used as the last steps of purification. A heterobifunctional complex with fully preserved enolase and phosphoglycerate mutase activities was synthesized with the use of a bifunctional reagent, N-succinimidyl 3-(2-pyridyldithio)propionate. Autoantibodies to the conjugate will be used for identifying the bienzymatic complex in vivo.
Assuntos
Encéfalo/enzimologia , Complexos Multienzimáticos/metabolismo , Fosfoglicerato Mutase/isolamento & purificação , Fosfopiruvato Hidratase/isolamento & purificação , Autoanticorpos/metabolismo , Cromatografia de Afinidade , Reagentes de Ligações Cruzadas , Humanos , Complexos Multienzimáticos/imunologia , Fosfoglicerato Mutase/metabolismo , Fosfopiruvato Hidratase/metabolismo , SuccinimidasRESUMO
Highly purified preparations of (ADP-ribose) polymerase were obtained from calf testis and thymus by chromatography on DNA-cellulose, hydroxyapatite and gel filtration. It was shown that the enzymes isolated from both sources under identical conditions have similar values of Mr, Vmax and Km in the reactions of autoribosylation and poly(ADP-ribosylation) of histone H1 as well as similar pH-dependencies of the catalyzed reactions.