[Detection of phenylalanine hydroxylase activity in human leukocytes and fibroblasts]

The data obtained indicate the presence of phenylalanine hydroxylase activity in human leucocytes and fibroblasts. The following methods were used: estimation of accumulation of the oxidized form of the pteridine cofactor after Ayling and coworkers and radiochemical method. Probably this activity is connected with cell membranes and can be solubilized by treatment of cells by Tritone X-100. The possibility of estimation of phenylalanine hydroxylase activity in leucocytes instead of liver bioptates for discrimination of homo -- and heterozygotes with PKU gene is assumptive.