[Determination of the enzymatic activity of lysine amidase]. / Opredelenie fermentativnoi aktivnosti lizinamidazy.

A technique is proposed for determining lysinamidase and aminolactamase activities of lysinamidase (EC 3.5.1.n.). It is based on spectrophotometric measurement of the optical density decrease of the substrate solution at 227 nm. For cyclic lysinamide L-alpha-amino-epsilon-caprolactam epsilon 227 M = 151 M-1.cm-1, for linear lysinamide epsilon 227 M = 73 M-1.cm-1, and for lysine epsilon 227 M = 5 M-1.cm-1. The technique is simple and requires no additional reagents.

[Choice of the initial enzyme correlation in immobilizing polyenzyme systems]. / Vybor iskhodnogo sootnosheniia fermentov pri immobilizatsii polifermentnykh sistem.

An optimal, in respect to productivity (activity X stability), enzyme ratio for immobilization of multienzyme systems was calculated by using the kinetic parameters (KM and Vmax), data on the stability and yield of each enzyme during immobilization. The experimental data, obtained during combined immobilization of invertase, mutarotase and glucose oxidase, illustrate the theoretical propositions.

[Determination of beta-mannanase activity by viscosimetric and spectrophotometric methods]. / Opredelenie aktivnosti beta-mannanazy viskozimetricheskim i spektrofotometricheskim metodami.

The activity of beta-mannanase from Bacillus subtilis was measured viscosimetrically and spectrophotometrically. As substrate galactomannane of Ceratonia siliqua was used. Relationships between the beta-mannanase activity and the substrate concentration as well as the enzyme content were investigated. The kinetic parameters of the enzymes obeying the Michaelis-Menten equation were calculated. It was found viscosimetrically that Vmax of the commercial enzyme preparation was 1.4 mucat/g (at pH 5.8 and 40 degrees) and Km was 0.6 mM. The viscosimetric method shows high sensitivity, whereas the spectrophotometric technique suits mass-scale analyses.

[Isolation and characteristics of immobilized L-glutamate decarboxylase]. / Poluchenie i kharakteristika immobilizovannoi L-glutamatdekarboksilazy.

Glutamate decarboxylase from Escherichia coli was immobilized on inorganic macroporous carriers by the glutaraldehyde, carbodiimide and bromacetyl methods, on silicagel coated with a layer of a glutaraldehyde and m-phenylene diamine copolymer, and by polyacrylamide gel incorporation. The efficiency of the above methods of immobilization was evaluated. The bromacetyl method was found to be the most efficient. The dependence of activity of soluble and immobilized Glu-decarboxylase upon pH, temperature, substrate concentration, and stability was established. The differences in the properties of soluble and immobilized Glu-decarboxylase were due to the substrate diffusion in pores of the carrier. The immobilized Glu-decarboxylase obtained showed high activity and stability.

[Preparation and charaterization of aminopolysterol immobilized invertase]. / Poluchenie i svoistva invertazy, immobilizovannoi na aminopolistirole.

Invertase from Saccharomyces cerevisiae was immobilized on aminopolysterol by adsorption, glutaraldehyde, carbodiimide or bromacetyl methods. The dependence of activity of invertase immobilized by the carbodiimide method upon pH, temperature and sucrose concentration was studied. The "effective" Michaelis constant of the immobilized preparation was 6 times higher than that of soluble inverase. At high sucrose concentrations (beginning with 0.2 M for immobilized and 0.9 M for soluble invertase) substrate inhibition was observed. The data on stability of immobilized invertase during refrigerated storage and in a working flow column were obtained.

[Thermostability of glucose oxidase immobilized on silica gel by different methods]. / Termostabil'nost' gliukozooksidazy, immobilizovannoi na silikagele razlichnymi, metodami.

Immobilization and thermostability of glucose oxidase immobilized on silica gel MCA-750 7 by different methods were studied. The process of inactivation was found to follow two stages that differed in their rate. The most stable preparations were produced by immobilization based on bromacetyl and glutaraldehyde methods.