The maintenance of prostatic acid phosphatase activity by proteins and polyamines

Abstract

1. 1. In the absence of protective substances, prostatic acid phosphatase in high dilution may be irreversibly inactivated, apparently by surface denaturation. 2. 2. Enzyme activity is maintained in the presence of certain proteins, polypeptides and amino-compounds; particularly long-chain polyamines. 3. 3. The protective effect of polyamines increases with the chain-length between terminal amino-groups. 4. 4. The effect disappears with the destruction of amino-groups, or with their conversion to amides. The α-amino groups of amino-acids are ineffective. 5. 5. Conversion of primary to secondary amines does not lessen the effect, and may even increase it. 6. 6. Treatment with formaldehyde, with the formation of polymers, may increase the effect. 7. 7. Complete hydrolysis of proteins destroys their protective action, and enzymic digestion reduces it to a variable extent. This can be explained on the assumption that the activity of proteins and polypeptides in this respect depends on the presence of basic side-chains, linked through the peptide chain to give an effect similar to that of the long-chain polyamines.