Plutonium Content in Soil Fractions of Various Sizes and Estimation of the Risks of the Chernobil Nuclear Power Plant Zone.

Based on the data from the literature the authors analyzed the methods used for the estimation of the risks of plutonium-contaminated areas. The analysis was based on the published data on the measured plutonium concentrations in the air and soil. To calculate plutonium concentrations in the near-surface air layer above the contaminated area a modification of the method of the load estimation from the mass was proposed: instead of the average plutonium specific activity in soil the authors suggested the use of the soil coefficient which consists of the sum of specific activities of every respirable fraction (size 0.

[Conjugates of pancreatic ribonuclease and ligand-free human serum albumin].

Conjugates of pancreatic RNase and ligand-free human serum albumin (LFHSA) have been obtained. The number of hydrophobic binding sites both for initial HSA and LFHSA has been determined by the polarised luminescence method. Interaction between RNase and HSA involves additional electrovalent linkage.

[Interaction of Bacillus intermedius 7P ribonuclease with ligand-free serum albumin].

The efficiency of the binding of RNase 7P molecules to albumin on cocondensation with the aim of producing the prolonged action forms of the enzyme can be increased by using ligand-free human serum albumin (LFHSA). The CD method showed that LFHSA underwent changes of the cooperative character under the action of acid and urea. On potentiometric titration the number of titrated groups of LFHSA decreased with time.

[Permeation of pancreatic ATPase through the blood-brain barrier into the cerebral parenchyma].

Penetration of exogenous RNAases, native and albumin polymer-bound, from circulation into the brain parenchyma was studied. Native pancreatic RNAase was found to extend through the hematoencephalic barrier; maximal enzymatic activity was detected within 15-30 min after administration into a rat tail vein. The enzyme activity was not observed within 90 min both in blood serum and brain tissue.

[Nuclease conjugates with ligand-free serum albumin].

In order to obtain nuclease and human serum albumin (HSA) conjugates with a high enzyme content it is proposed to use a ligand-free HSA. The ligands are removed with the help of a strong anion exchanger. A two-stage procedure of conjugate preparation is proposed.

[Hetero-oligoproteins containing pancreatic ribonuclease--enzyme conjugates of prolonged action].

Conjugates containing blood serum albumin and pancreatic ribonuclease, produced by means of polycondensation reaction, exhibited higher half-life in rabbit circulation as compared with non-modified enzyme. Presence of the protein-carrier contributed to elevation of the ribonuclease therapeutic efficiency and enabled to decrease the quantity of injections.

[The effect of chemical modification of ribonuclease A by serum albumin on its catalytic properties].

The effect of chemical modification of ribonuclease A on its catalytic properties was studied. The kinetic parameters were calculated by using the Eisental and Cornish-Bowden direct linear plot. The Km value found for ribonuclease A conjugates with human serum albumin are comparable with those for the native enzyme whereas the Vmax value of the modified enzyme exceeds the maximum velocity of the enzymatic reaction of native ribonuclease A.

[Enzymatic and conformational stability of polymeric complexes of alpha-amylase].

The enzymatic and conformational stability of Bacillus subtilis alpha-amylase and its polymeric complexes in acid media and subsequent renaturation in weakly alkaline media were investigated. The following parameters of alpha-amylase secondary structure were determined from circular dichroism spectra: helical units -25%, beta-structures -9%; beta-turns -13%; disordered conformations -53%. After complexation with polymethacrylic acid (PMAA) the alpha-amylase secondary structure did not change, and the tertiary structure underwent only small local changes.

[Conformation properties and enzymatic activity of pancreatic ribonuclease in soluble complexes with sodium dextran sulfate].

Effect of complex formation with dextran sulfate (DS) (substitution degree 1.3, molecular mass 500 thousand) on RNAse enzymic activity. its spatial structure and conformation stability was studied.

[Reversibility of the acid inactivation of immobilized alpha-amylase].

The process of reactivation of acid-inactivated alpha-amylase of Bacillus subtilis in weakly alkaline media was examined. The reactivation of alpha-amylase immobilized on carboxyl polyelectrolytes developed in a larger measure than that of the native enzyme. The stabilizing effect of the cross polymer decreased as its porosity increased.

[Isolation and study of physico-chemical properties of alpha-amylase from Bacillus subtilis].

By chromatography on ultragel ACA-54 alpha-amylase was isolated from the enzymic preparation amylosubtilin G10x. As compared to the initial preparation, the specific activity of the purified enzyme per mg increased 25-fold. The major physico-chemical characteristics of alpha-amylase were determined.

[Modification of pancreatic ribonuclease activity in complexes with polyanions].

Carboxymethylcellulose, carboxymethylchitin, sulfoethylcellulose and dextrane sulfate interact with pancreatic ribonuclease. In comparison with ribonuclease activity the activity of formed complexes changes differently at the stages of transesterification and hydrolysis, and at each stage the effect of polymers on ribonuclease activity essentially differs. The use of ribonuclease-dextrane sulfate complex in the reaction of uridylyl-(3' leads to 5')-cytidine synthesis demonstrated that the protein synthetic activity completely retained when hydrolytic activity was considerably suppressed.