Penicillin (C16H17N2NaO4S; MW 356.40) has approx. 1650 U/mg (1 Mio U = approx. 599 mg). Benzyl-penicillin sodium salt, penicillin G sodium salt, is a biosynthetic amino acid-antibiotic. Penicillin is predominantly active against Gram positive bacteria. Streptomycin-sulfate C21H39N7O12)2-3H2SO4; MG 1457.40 is an aminoglycoside antibotic derived from Streptomyces griseus. Streptomycinsulfate has a wide range of action.