Effects of some connective-tissue active drugs on protocollagen proline hydroxylase activity.

The effect on protocollagen proline hydroxylase of drugs reported to be capable of inducing the lupus erythematosus syndrome and in some way acting on connective tissue and inflammation was studied in an in vitro system for the hydroxylation of 14C-Pro-labelled protocollagen. Some derivatives were also studied. It was found that benzoic acid and phenothiazine derivatives, hydroxyphenols, (+)catechin, beta-amino propionitrile, certain B vitamins, dihydrazinophthalazine, cysteine and dimethylcysteine were inhibitors of PPH. The chelation of Fe2+ions by the compounds mentioned is suggested to be essential.