Pyridoxine (pyridoxamine) phosphate oxidase activity in the red cell.
A method has been developed for the measurement of red cell pyridoxine (pyridoxamine) phosphate oxidase activity. The more stable substrate, pyridoxamine phosphate, was incubated with a red cell haemolysate and the product pyridoxal phosphate was measured by Lactobacillus casei microbiological assay. A wide range of oxidase activities was found in control subjects (6-136 ng pyridoxal phosphate/g Hb x 10(-2)). There is a close correlation between the rate of conversion of pyridoxine to pyridoxal phosphate in whole blood and the oxidase activity. There was a marked increase in both after oral riboflavin. These results suggest that the oxidase plays a large part in the regulation of vitamin B-6 metabolism in red cells.
D000328:Adult; D004912:Erythrocytes / Q000201:enzymology*; D006454:Hemoglobins; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008875:Middle Aged; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000097:blood*; D011734:Pyridoxaminephosphate Oxidase / Q000097:blood*; D011736:Pyridoxine / Q000097:blood; D012256:Riboflavin / Q000494:pharmacology
D006454:Hemoglobins; D011734:Pyridoxaminephosphate Oxidase; D000587:Oxidoreductases Acting on CH-NH Group Donors; D011736:Pyridoxine; D012256:Riboflavin