Purified protoplasmic peptides of mycobacteria: chemical composition of a tuberculin-active glycopeptide.

A tuberculin-active glycopeptide containing eight different amino acids and glucose was isolated from the protoplasm of Mycobacterium tuberculosis. A molecular weight of 4,000 to 5,000 was established by Sephadex gel filtration; other analyses showed a peptide to carbohydrate ratio of 9:1. These observations suggest a tentative composition of 3 to 4 residues of glucose, 12 residues each of aspartic and glutamic acids, 3 residues each of lysine, glycine, and serine, and 1 residue each of arginine, threonine, and alanine.