Purification and Properties of Three β-N-Acetylglucosaminidases from Lactobacillus casei ATCC 27092

Three β-N-acetylglucosaminidases, GlcNAcase A, B, and C, were purified from the culture fluid of Lactobacillus casei ATCC 27092, and the molecular weights of these enzymes were estimated to be 54,000, 51,000, and 44,000, respectively, by SDS-PAGE. The production of these GlcNAcases was accelerated by the addition of N-acetylglucosamine to the culture. These enzymes had pIs of about 5.2, an optimum pH of 5.0-5.5, and an optimum temperature of 37-40°C. The K m values of GlcNAcase A, B, and C for p-nitrophenyl-β-N-acetylglucosamine were 0.85, 1.30, and 1.04 mM and those for p-nitrophenyl-β-N-acetylgalactosamine were 39.6, 57.7, and 60.8 mM, respectively.