Methods and their evaluation for the estimation of vitamin B6 levels in man. 5. Serum pyridoxal-5-phosphate determination: method and comparison of methods
Leinert, J.; Simon, I.; Hötzel, D.
International Journal for Vitamin and Nutrition Research. Internationale Zeitschrift für Vitamin- und Ernahrungsforschung. Journal International de Vitaminologie et de Nutrition 53(2): 156-165
1983
ISSN/ISBN: 0300-9831 PMID: 6309690 Document Number: 214448
Methods and Their Evaluation to Estimate the Vitamin B6-Status in Human Subjects. V. S-PLP-Determination: Method and Comparison of Methods. A method to determine the plasma pyridoxal 5-phosphate (PLP) basing on the enzymatic decarboxylation of 1-14C-l-tyrosine and the measurement of the radio-active 14CO2 is described. Its efficiency is discussed in comparison with other methods. High specificity, precision, accuracy, and sensitivity are demonstrated. The developed equipment allows to analyse a great number of samples and minimizes the risk of radio-active contamination. The commercial apoenzyme preparations are different in quality and require purification. Apoenzyme lots with high genuine content of PLP are useless. Storage tests at 4 degrees C, -18 degrees C, and -196 degrees C show stability of the samples for one day, 30 days, and at least 10 weeks.