Kynurenine formamidase activity in the American cockroach

Kynurenine formamidase is widely distributed in the tissues of the American cockroach, Periplaneta americana, but is highest in activity in the fat body. Enzyme from this tissue is found in the soluble fraction of the cell, has no sharp pH optimum, and exhibits an apparent K m value of 1.43 × 10 −3 M. Sodium bisulphite is a strong inhibitor of the reaction, and has the characteristics of an uncompetitive inhibitor. Formamidase from pearl and lavender eye color mutant stocks has a tissue distribution pattern and activity characteristics essentially identical to those of wild type. Possible biochemical lesions for these mutant stocks are suggested.