Alpha-N-acetylgalactosaminidase from marine bacterium Arenibacter latericius KMM 426T removing blood type specificity of A-erythrocytes

An -N-acetylgalactosaminidase IV able to remove blood type specificity of human A(II)-erythrocytes and not effecting B(III)-erythrocytes was isolated from the marine bacterium Arenibacter latericius KMM 426^T. The -N-acetylgalactosaminidase IV preparation exhibits high activity during inhibition of hemagglutination with blood group substance A containing determinants analogous to A-erythrocytes. The enzyme has a pH optimum from 7.0 to 8.0 and completely retains its activity during 30-min heating at 50°C and for a week at 20°C. The enzyme can be stored under the sterile conditions for any length of time at 4°C, but it does not withstand freezing. The -N-acetylgalactosaminidase is resistant to NaCl; for p-nitrophenyl--N-acetyl-D-galactosaminide, the K _m is 0.38 mM. The molecular mass of the enzyme determined by gel filtration is 84 kD.