title: [Methods and their evaluation for the estimation of vitamin B6 levels in man. 5. Serum pyridoxal-5-phosphate determination: method and comparison of methods].
abstract: 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.
mesh_terms: D002250:Carbon Radioisotopes; D003653:Decarboxylation; D006801:Humans; D010744:Phosphoric Monoester Hydrolases / Q000097:blood*; D011736:Pyridoxine / Q000097:blood*; D014439:Tyramine / Q000378:metabolism; D014445:Tyrosine Decarboxylase / Q000378:metabolism
chemical_list: D002250:Carbon Radioisotopes; C022493:pyridoxal-5-phosphatase; D010744:Phosphoric Monoester Hydrolases; D014445:Tyrosine Decarboxylase; D011736:Pyridoxine; D014439:Tyramine
vernacular_title: Methoden und deren Wertung zur Bestimmung des Vitamin-B6-Versorgungszustandes beim Menschen. 5. Mitteilung: "S-PLP-Bestimmung: Methode und Methodenvergleich".