Some Properties of Tyrosine Aminotransferase from Trichoderma viride

SUMMARY: Tyrosine aminotransferase, induced in Trichoderma viride by l-tyrosine, was isolated from the culture medium, partially purified and characterized. The enzyme was inducible by both l- and dl-tyrosine, although l-tyrosine was the better inducer. The enzyme required l-tyrosine and α-ketoglutarate as amino donor and amino acceptor, respectively. Its pH optimum in 50 mm-potassium phosphate buffer was 7.6, the apparent Michaelis constants were 0.5 mm for l-tyrosine and 0.25 mm for α-ketoglutarate; it had a molecular weight of 110000.