[Specificity of fungal alpha-glucosidases].

Studies of substrate and cosubstrate specificities of mould alpha-glucosidases suggest that the binding site of the active center of mould alpha-glucosidase consits of two subsites--glucone and aglucone ones. The glucone site is capable to bind glucose and mannose, whereas the aglucone one- some compounds whose affinity for the enzyme may be expressed as follows: glucose greater than galactose greater than paranitrophenol greater than or equal to glycerol greater than ethanol approximately equal to methanol. Upon interaction of enzyme with alpha-D-glucoside the formation of a productive enzyme-substrate complex occurs when the glucosyl residue located at the non-reducible end of the substrate molecule occupies the glucone subsite and aglucone of the substrate occupies the aglucone subsite of the enzyme.

[Determination of the glucoamylase activity in amylolytic preparations].

Glucoamylase capacity of amylolytic preparations was determined with respect to the initial rate (VO) of the glucose synthesis from starch when treated with the preparations tested. The concentration of free glucose (y) was assayed, using a glucooxidase reagent after 5, 10 and 20 min hydrolysis. This method takes into consideration the y -- t function which may be non-linear due to the effect of a number of factors (occurrence of alpha-amylase, enzyme inactivation, etc.

[Characteristics of transglucosilase from Aspergillus batatae].

Action of transglucosilase from Asp. batatae on different substrates is studied. The ratio of transglucosilase (upsilont) and hydrolase (upsilonh) activities on maltose under the action of transglucosilases from different origins is estimated.