A simplified method for determination of pyridoxal phosphate in biological samples

A new method for the determination of pyridoxal phosphate in plasma and in cerebrospinal fluid is described. It is based on the generally accepted apotyrosine decarboxylase method, but, in stead of following the decarboxylation rate using 14C- och 3H-labelled tyrosine, a high performance liquid chromatography (HPLC) method for separation of tyrosine and tyramine is used. This procedure is recommended as it is less time consuming and avoids utilizing radioactive material.