Title: [85] Microassay of pyridoxal phosphate usingl-tyrosine-1-14C and tyrosine apodecar☐ylase
Abstract: This chapter discusses the assay of pyridoxal phosphate (pyridoxal-P) and preparation of tyrosine apodecarboxylase. The assay is based on the pyridoxal phosphate (pyridoxal-P)-dependent enzymatic decarboxylation of L-tyrosine by tyrosine decarboxylase. With L-tyrosine-1-14C as the substrate, in the presence of tyrosine apodecarboxylase and pyridoxal-P, 14CO2 that is produced in the reaction is trapped and counted directly in a liquid scintillation spectrometer. The concentration of pyridoxal-P in the standard solution is determined spectrophotometrically from its molar extinction coefficient of 6550 at 388 mμ in 0.1N NaOH and 4900 at pit 7.0. A plot of disintegrations per minute in CO2 versus amount of standard pyridoxal-P is used to determine the pyridoxal-P content of the unknown sample. The assay is linear between 1 and 8 ng of pyridoxal-P.
Publication Year: 1970
Publication Date: 1970-01-01
Language: en
Type: book-chapter
Indexed In: ['crossref']
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Cited By Count: 38
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