Reactions of Synthetic Vitamin K Compounds to SH Group produced in Spoiled Bacterial Medium

Antibacterial powers of VK compounds in the medium spoiled by microbe were compared with those in the fresh medium, and the following results were obtained. (1) When tested in the glucose-salt or caseinhydrolyzate-glucose-salt medium, the antibacterial activities of VK compounds were the same both in the fresh and spoiled media. When tested in the peptone-glucose-salt medium, however, VK compounds inhibited the growth of microbe less remarkably in the spoiled medium than in the fresh medium. (2) There was a considerable amount of a group active to p-chloromercuribenzoate in the spoiled peptone-glucose-salt medium, and the group also had high activity to VK compounds. (3) Consequently, it was considered that free SH groups occurred in the spoiled peptone, and the group interfered with the antibacterial action of VK compounds.