title: [Determination of half-life time for the key enzymes of the pentose phosphate pathway--glucose-6-phosphate dehydrogenase and transketolase].
abstract: Using hormonal induction by thyroxin, the half-life time and the rate constants for the synthesis and degradation of glucose-6-phosphate dehydrogenase and transketolase were determined. It was shown that the mechanisms of activation of these enzymes by thyroxin are different. Under hyperthyrosis an increase in the activity of glucose-6-phosphate dehydrogenase is induced by a decrease (2-fold) of the degradation rate constant; the rate constant of synthesis is not changed thereby, while the half-life time for the enzyme increases 2-fold. The activation of transketolase in this case can be accounted for by an almost 1,5-fold increase in the rate of the enzyme synthesis, whereas the degradation rate constant and the half-life time of the enzyme remain practically unchanged.
mesh_terms: D000818:Animals; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism*; D006207:Half-Life; D007700:Kinetics; D008297:Male; D009206:Myocardium / Q000201:enzymology; D010428:Pentosephosphates / Q000378:metabolism*; D051381:Rats; D013974:Thyroxine / Q000494:pharmacology*; D014174:Transketolase / Q000378:metabolism*
chemical_list: D010428:Pentosephosphates; D005954:Glucosephosphate Dehydrogenase; D014174:Transketolase; D013974:Thyroxine
vernacular_title: Opredelenie periova poluzhizni kliuchevykh fermentov pentozofosfatnogo puti--gliukozo-6-fosfatdegidrogenazy i transketolazy.