抄録
The isoenzymes of aspartate aminotransferase, m-AST, s-AST were purified from human liver. The assay conditions of AST activity were investigated by use of the purified AST isoenzymes and patient's sera with respect to substrate and pyridoxal 5'-phosphate (PALP).
The affinities of m- and s-AST for aspartate were remarkedly differed, Km values were 0.5mM and 3.1mM, respectively. Over 100mM of aspartate, m-AST activity was inhibited, whereas s-AST was none.
The activation of AST activity by PALP were observed in all these specimens. The preincubation of specimen with PALP alone showed much more rapid activation than with PALP plus aspartate. The inhibitory action of aspartate to PALP binding was excluded by the short preincubation with PALP and specimen.
