US Patent 7892784 Lactam ring-opening enzyme and use thereof

An enzyme capable of reducing the antibiotic activity (i.e., toxicity) of streptothricin with respect to eukaryotic cells without sacrificing antibiotic activity with respect to prokaryotic cells is provided along with a streptothricin derivative having reduced toxicity with respect to eukaryotic cells while retaining antibiotic activity with respect to prokaryotic cells, and a manufacturing method thereof. By opening the lactam ring of streptothricin, a protein having the amino acid sequence according to SEQ ID NO: 2, 4, 6, 8, 10, 12, 14 or 16 of the invention can reduce the antibiotic activity of streptothricin D with respect to eukaryotic cells without sacrificing antibiotic activity with respect to prokaryotic cells.