[Hypochromic effect of signal attenuation in 31P-NMR spectra of linear polyphosphates].

Chemical shifts in 31P-NMR spectra of linear polyphosphates were studied. In each polyphosphate species tested, the sum of signal intensities of the internal (core) phosphate groups was proportional to the concentration of each polyphosphate, but the contribution of such groups to the total intensity of the signal decreased with increasing the length of the polyphosphate chain. An equation for estimating the polyphosphate chain length in biological objects taking into account a decrease in the 31P-NMR spectral intensity is proposed.

[Isolation and certain properties of mutant alkaline phosphatase of Escherichia coli].

Natural and mutant alkaline phosphatases with amino acid substitutions in the processing site and N-terminal domain of the mature polypeptide chain Val for Ala(-1), Gln for Glu (+4) and simultaneously Gln for Glu (+4) and Ala for Arg (+1) have been isolated from the periplasm and cultural fluid of E. coli. It has been found that these substitutions have little effect on the dependence of the enzyme activity on pH, ionic strength and temperature but influence its isoenzymic spectrum and decrease (almost twofold) the maximal rate of the enzyme-catalyzed reaction.

[The effect of elymoclavine and its derivatives on various enzymes of the gastrointestinal tract].

The influence of elymoclavine, elymoclavine hydrochloride, elymoclavine hydrobromide, 2-bromelymoclavine, 2-bromelymoclavine hydrobromide on the initial rater of enzymatic hydrolysis of cytidine-2',3'-monophosphate by RNase A and of N-alpha-benzoyl-DL-tyrosine-p-nitroanilide by alpha-chymotrypsin has been investigated. It is shown that all the compounds have the features of various types of inhibitors of RNase A and alpha-chymotrypsin with the exception of elymoclavine which shows all features of a catalytic activator of RNase A.

[Enzymes of a bacteriolytic lysoamidase preparation. Various properties of bacteriolytic protease L2].

Bacteriolytic proteinase L2 is able to cleave fluorogenic synthetic tripeptide anthranoyl-alanyl-alanyl-phenylalanyl-nitroanilide (Abz-Ala-Ala-Phe-pNA) at the bond between phenylalanine and p-nitroaniline. Optimal conditions of the tripeptide cleavage have been determined: pH 6.7 + 0.

[Various physico-chemical and kinetic properties of metalloproteinase from bacteriolytic lysoamidase preparation].

The amino acid composition of metalloproteinase was determined. It was shown that the enzyme is made up of four cysteinyl residues which makes it distinct from other known neutral metalloproteinases from Bacillus brevis, Bacillus subtilis and thermolysine that are devoid of cysteinyl residues. The inhibiting effect of amino acids and some di- and tripeptides on the metalloproteinase activity was studied.

[Study of the inhibition of neutral phosphatase from Pseudomonadaceae by derivatives of its substrates].

The inhibition of neutral phosphatase isolated from the bacteria of the Pseudomonadaceae family by various fragments of the enzyme-hydrolyzed R-O-PO3H2 substrates, inorganic orthophosphate (KH2PO4) and its analogs as well as by adenine, adenosine, alcohols, sugars and amino acids, was studied. It was demonstrated that among other compounds tested only the orthophosphoric acid anions (H2PO4-) exhibit the properties of strong associative inhibitors (K1Vi = 4.35.

[Structural identity of active sites of RNases].

It is known that the affinity of all nucleoside monophosphate isomers for RNAase active sites increases in the following order: 5'-NMP----3'-NMP----2'-NMP, irrespective of the RNAase type (pyrimidine-specific, guanine-specific or non-specific) and stage of activity (transferase, hydrolase). It is known also that the nucleotides with the same degree of isomerism have substantially the same conformation. It was thus supposed that the structure of active sites of RNAase has common features with a closer similarity in case of pyrimidine-specific (EC 3.

[Distribution of the inhibiting activity among bivalent metal cations].

The inhibition coefficients (beta) of bovine pyrimidine-specific RNAase A by bivalent metal cations were determined. The effect of ionization potentials, hydration energy and ionic radii of cations on their inhibiting activity is discussed.

[Comparative study of properties of periplasmic and membrane-bound alkaline phosphatase of E. coli].

The properties of three forms of periplasmic and one form of membrane-bound alkaline phosphatase of E. coli were studied. A practically complete agreement between the conditions for optimal activity of these enzymes (pHopt 9.

[Interaction of intracellular RNAase from Aspergillus clavatus with derivatives of its substrates].

Using spectrophotometric and kinetic methods and also the methods of protection of Aspergillus clavatus RNAse (EC 3.1.4.

[Activation parameters for the cleavage reaction of cytidine-2',3'-monophosphate catalyzed by Penicillium brevicompactum and Aspergillus clavatus RNAses].

On the basis of coincidence of all activation parameters (E, deltaH*, deltaF* and deltaS*) for the reaction of cleavage of cytidine-2';3'-monophosphate catalyzed by "acid" (pH-optimum 4.7) nonspecific RNAses from Aspergillus clavatus and Penicillium brevicompactum (EC 3. 1.

[Study of splitting dinucleoside monophosphates by Penicillium brevicompactum RNAse].

In studies of splitting of transferase substrates cytidylyl-(3' leeds to 5')-adenosine and adenylyl-(3'leds to to 5')-cytidine by Penicillium brevicompactum RNAase the pH-optimum activity of enzyme has been found to fall within the range of 4.7 +/- 0;1; temperature optimum--within 41 degrees--43 degrees C; adenine-nucleotides, their constituent components and polyphosphates display the properties of competitive inhibitors on splitting substrates and that amino-acid residues (presumably weakly- and strongly-protonated imidasole groups) function in the active site of this enzyme (pK 5.88 +/- 0,1 AND 6.

[The pH dependence of kinetic parameters of Penicillium brevicompactum RNAase].

The effect of pH on the kinetic parameters (Km and Ki) for extracellular acid Penicillium brevicompactum RNAse (pH max 4.7+/-0.1), non-specific to the chemical nature of nucleic bases, was studied.

[A spectrophotometric study of Penicillium brevicompactum RNAase complex formation with adenine nucleotides].

Spectrophotometric study of extracellular Pen. brevicompactum RNAse interaction with adenyl nucleotides and constituents have been carried out. It is states that: 1) complex RNAse--nucleotide is formed by association of one enzyme molecule with one nucleotide molecule; 2) all the nucleotide components base sugar and phosphate, take part in the formation of this complex; 3) for the effective association of this complex it is necessary to have a high correspondence (complementaryty) of nucleotide geometric configuration to the space composition of the active site of RNAse.

[Substrate specificity of Aspergillus clavatus intracellular acid RNAase].

Substrate specificity of intracellular acid RNAse from Aspergillus clavatus, has been studied using different RNAs, synthetic polynucleotides and diribonucleoside monophosphates as substrates. The enzyme was shown to be a RNAse, non-specific to the chemical nature of bases adjacent to the disrupted phosphodiesther bonds in the molecules of RNA. It has been demonstrated that the order of nucleotide release from RNA coincides with the order of weakening of the enzyme binding to substrates XpY, depending on the base X.

[Inhibition of Aspergillus clavatus intracellular RNA-ase by nucleotides and the components comprising them].

The constants of inhibition by the nucleotides and constituting components catalysed by intracellular "acid" (pHopt 4.7), non-specific RNAse from Asp. clavatus (EC 3.