Orlov D N, Nezvetskiĭ A R, Orlova T G, Petrukhin O V, Orlov N Ia
Biofizika. 2014 Sep-Oct;59(5):837-42.
The supposition that nucleoside diphosphate kinase is the enzyme that phosphorylates transducin beta-subunits on one of the histidine residues (His-266) has been analyzed. It stands the reason that 1) this enzyme is multifunctional and plays in particular the role of protein histidine kinase; and 2) the phosphorylated beta-subunit of transducin may activate transducin via the mechanism of transphosphorylation. Nevertheless, in our experiments, in which different forms of transducin preparations were incubated with α- and β-isoforms of recombinant rat NDP kinase in the presence of [γ32P]ATP or [γ32P]GTP (specific activity of about 1 Ci/mmol) followed by separation of proteins by electrophoresis and-gel radio-autography, the phosphorylation of the transducin beta-subunit wasn't succeeded to be found. The negative result of our experiments most likely implies that the major part of transducin beta-subunits in the preparations has already been phosphorylated via a process that takes place in vivo.
关于核苷二磷酸激酶是使转导素β亚基在其中一个组氨酸残基（His-266）上磷酸化的酶这一假设已进行了分析。有理由认为：1）这种酶具有多功能，尤其发挥蛋白质组氨酸激酶的作用；2）转导素的磷酸化β亚基可能通过转磷酸化机制激活转导素。然而，在我们的实验中，将不同形式的转导素制剂与重组大鼠NDP激酶的α和β同工型在[γ32P]ATP或[γ32P]GTP（比活性约为1 Ci/mmol）存在下孵育，随后通过电泳分离蛋白质并进行凝胶放射自显影，未成功发现转导素β亚基的磷酸化。我们实验的阴性结果很可能意味着制剂中转导素β亚基的大部分已通过体内发生的过程被磷酸化。
