[Stability of enzymes inactivating aminoglycoside antibiotics].

Stability of aminoglycoside phosphotransferases, adenylyltransferases and acetyltransferases isolated from various sources was studied. The enzymes were characterized by different substrate profiles. They were stored at a temperature of -10 degrees C in the form of frozen solutions or at a temperature of 4 degrees C in the lyophilized form. It was shown that lyophilization markedly increased the stability of the enzymes inactivating aminoglycoside antibiotics. Aminoglycoside phosphotransferases and adenylyltransferases with streptomycin as substrate were less stable than aminoglycoside phosphotransferases with neomycin as substrate. Aminoglycoside acetyltransferases from Streptomyces fradiae 918 producing neomycin were least stable among the enzymes studied. Lyophilized enzymes as a possible stabilizer of ATP added to the preparations had no significant effect on their stability during storage.