Borzova N. Alpha-N-acetylgalactosaminidase and alpha-galactosidase of Aspergillus niger 185ш

The thesis is focused on the isolation and investigation of enzyme with alpha-N-acetylgalactosaminidase and alpha-galactosidase activity from culture liquid A. niger 185ш . The screening for a-N-acetylgalactosaminidase among 1514 cultures of micromycetes, yeast and bacteria permit to select strain-producer A. niger 185ш. Its trophic characteristics examined and different factors have been investigated for their effect on the process of biosynthesis of extracellular alpha-N-acetylgalactosaminidase and alpha-galactosidase. A number of natural and synthetic agents possess increasable effect on synthesis of the above mentioned enzymes (50-200 %). The enzyme was purified about 600-fold, activity of alpha-N-acetylgalactosaminidase and alpha-galactosidase in enzyme preparation were 10,5 and 25 U/mg protein, respectively. The enzyme physical and chemical properties, catalitic characteristics and substrate specificity were explored. There are absent groups containing the atoms of metals in the enzyme molecule. Glycosidase active center appears to contain the carboxyl group of asparagine or glutamine acids and imidazole histidine group.Sulfhydryl groups are not involved in the catalysis; however, it's possible they may play essential role in supporting the active conformation of the protein molecule. Preparation of enzyme was nontoxic, but pyrogenic. Serological relationship between A.niger enzyme and Cladosporium cladosporioides alpha-galactosidase was found.