Stability of mammalian lens phosphofructokinase.
Two interconvertible phosphofructokinase (PFK) forms were found in rat and human lenses; whereas only one predominant form was found in calf lens. PFK isolated from these lenses possessed a common property, i.e., pH-dependent cold (or acid) lability. The inactivation was prevented by including either adenosine triphosphate (ATP) or fructose-6-phosphate (fru-6-P) in the incubating media. The protective effect of ATP or fru-6-P was complete in rat or calf lenses. In human lens, although fru-6-P was fully protective, ATP protected only partially. The inactivation could be reversed by addition of fru-6-P, but not ATP, to the incubating media at 37.5 degrees C. Lens organ culture studies showed that the depletion of lenticular ATP seemed to precipitate the loss of PFK.
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D002417:Cattle; D003080:Cold Temperature; D004355:Drug Stability; D004789:Enzyme Activation / Q000187:drug effects; D004793:Enzyme Reactivators; D005636:Fructosephosphates / Q000494:pharmacology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007908:Lens, Crystalline / Q000201:enzymology*; D009924:Organ Culture Techniques; D010732:Phosphofructokinase-1 / Q000378:metabolism*; D051381:Rats
D004793:Enzyme Reactivators; D005636:Fructosephosphates; D000255:Adenosine Triphosphate; D010732:Phosphofructokinase-1