[The phosphorylation state of transducin beta-subunits].
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.
D N
DN
Orlov
A R
AR
Nezvetskiĭ
T G
TG
Orlova
O V
OV
Petrukhin
N Ia
NIa
Orlov
D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D002417:Cattle; D006160:Guanosine Triphosphate / Q000378:metabolism*; D008297:Male; D009701:Nucleoside-Diphosphate Kinase / Q000378:metabolism*; D010766:Phosphorylation; D020033:Protein Isoforms / Q000378:metabolism; D021122:Protein Subunits / Q000378:metabolism; D051381:Rats; D015293:Transducin / Q000378:metabolism*
D020033:Protein Isoforms; D021122:Protein Subunits; D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate; D009701:Nucleoside-Diphosphate Kinase; D015293:Transducin