Studies on Acid Hydrolases in Adult and Foetal Tissues ACID p - NITROPHENYL PHOSPHATE PHOSPHOHYDROLASES OF ADULT GUINEA - PIG LIVER By M . W . NEIL AND MARIAN

Some tissues contain more than one enzyme exhibiting 'acid-phosphatase' action and the partial separation of such enzymes has been reported, e.g. from rat liver (Goodlad & Mills, 1957; Barka, 1961 a, b) and from Escherichia coli (Rogers & Reithel, 1960). Among the factors that make the interpretation of experimental observations on 'acid-phosphatase activity' difficult are (a) in the earlier work, lack of knowledge of the lysosomal sequestering of acid P-glycerophosphate phosphohydrolase (/3-glycerophosphatase) and the conditions in which it is released, (b) the variety of substrates used for assay coupled with a lack of information concerning the identity of the enzyme(s) responsible for the hydrolysis ofany given substrate and (c) the wide diversity of properties of 'acid phosphatases', both from different tissues within a species and from similar tissues in different species. Some of these inherent difficulties are illustrated by the work of Macdonald (1961) on the phenyl phosphate-phosphohydrolase (phenyl phosphatase) activity of mouse-liver homogenates and the subsequent interpretations of the results obtained (Neil, 1961; Macdonald, 1962). The present work is concerned principally with the differentiation of guinea-pig-liver enzymes that hydrolyse /-glycerophosphate and p-nitrophenyl phosphate in acid solution. Some of the results of this work have been briefly reported (Neil & Horner, 1962).