Malanchuk V. Penicillium canescens 239 and Cladosporium cladosporioides 189 a-galactosidases.

Thesis is focused on the production and investigation into the highly specific a-galactosidases of fungus origin. Screening for a-galactosidases among 2600 cultures of micromycetes, yeast and bacteria as a result of which 2 promising producers Penicillium canescens 239 and Cladosporium cladosporioides 189 were identified, their trophic characteristics examined and cultivation conditions optimized. Highly active a-galactosidase preparations were isolated from the culture liquid and purified to homogenous state, their physical and chemical properties, mechanism and specific effects were explored. Both a-galactosidases were found to be the glycoprotein nature showing high content of the dicarbonic and hydrophobic aminoacids and presence of the mannose, arabinose, ramnose and glucosamine in their carbohydrate moiety. a-Galactosidase active center appears to contain the imidazole histidine group and carboxyl group of asparagine acid. The hypothetical scheme for the "two-step" mechanism of the enzyme effect was proposed. a-Galactosidase of P.canescens 239 was shown to be able to split off the determinant a-1,3-bound D-galactose from the B(III)-erythrocyte membrane glycoconjugates with the transformation of the latter into the universal donor 0(I)-erythrocytes; both a-galactosidase preparations appeared effective during hydrolysis of the oligosaccharides in the soybean milk to easily digested sugars, galactose and sucrose.