The effects of pyrimidine and purine nucleotides on sialyltransferase activity in bovine neurosensory retina.
Effects of nucleotide phosphates on the sialyltransferase activity in the neurosensory retina of the bovine eye were studied. Enzyme activity was assayed using cytidine monophosphate-[14C]-N acetylneuraminic acid as a substrate and desialylated fetuin as an exogenous acceptor. Cytidine-5'-diphosphate and adenosine triphosphate inhibited the enzyme activity. Uridine diphosphate and guanosine diphosphate increased the enzyme activity at low concentrations and decreased the activity at high concentrations. Cyclic adenosine monophosphate and cyclic guanosine monophosphate increased the enzyme activity at concentrations up to 8 mM. It is thus concluded that sialyltransferase activity of the neural retina may be affected by various nucleotides, its alteration depending on either the type of nucleotides or their concentration.
Unoki
K
K
Department of Ophthalmology, Kagoshima University Faculty of Medicine, Kagoshima-shi, Japan.
Uehara
F
F
Muramatsu
T
T
Ohba
N
N
D000818:Animals; D002417:Cattle; D004795:Enzyme Stability; D011685:Purine Nucleotides / Q000494:pharmacology*; D011742:Pyrimidine Nucleotides / Q000494:pharmacology*; D012160:Retina / Q000187:drug effects / Q000201:enzymology*; D012799:Sialyltransferases / Q000378:metabolism*; D013379:Substrate Specificity; D000094802:beta-D-Galactoside alpha 2-6-Sialyltransferase
D011685:Purine Nucleotides; D011742:Pyrimidine Nucleotides; D012799:Sialyltransferases; D000094802:beta-D-Galactoside alpha 2-6-Sialyltransferase