In vivo operation of the pentose phosphate pathway in frog oocytes is limited by NADP+ availability.
Evolution of CO2 from labelled glucose microinjected into frog oocytes in vivo may be ascribed to the pentose-P pathway, as measured by radioactive CO2 production from [1-(14)C] and [6-(14)C]glucose. Coinjection of NADP+ and [14C]glucose significantly stimulated 14CO2 production. The effect depends on the amount of NADP+ injected, half maximal stimulation being obtained at 0.13 mM. The increase in CO2 production was also observed with microinjected glucose-1-P, glucose-6-P or fructose-6-P used as substrates. Phenazine methosulfate, mimicked the effects of NADP+. A high NADPH/NADP+ ratio of 4.3 was found in the cells, the intracellular concentration of NADP+ being 19 microM.
Preller
A
A
Departamento de Biologia, Facultad de Ciencias, Universidad de Chile, Santiago. apreller@abello.dic.uchile.cl
Guixé
V
V
Ureta
T
T
D000818:Animals; D005260:Female; D005947:Glucose / Q000378:metabolism*; D009249:NADP / Q000378:metabolism*; D009865:Oocytes / Q000378:metabolism*; D010427:Pentose Phosphate Pathway; D011894:Rana pipiens; D013379:Substrate Specificity; D014982:Xenopus laevis
D009249:NADP; D005947:Glucose