[Isolation and structure of novel peptide inhibitor of HIV-1 integrase from marine polychaetes].

A homogeneous peptide with m683 Da which inhibits HIV-1 integrase with IC50 3 x 10(-5) M was separated from aqueous extracts of marine worm Eunicidae sp. by multi-stage chromatography purification. The structure Asp-Leu-Hse-His-Ala-G1n was proposed for this peptide according to the amino acid analysis, automated amino acid Edman sequencing, TLC with the witness and homoserine MS/MS fragmentation. The proposed structure is the first example of natural peptide containing amino acid homoserine residue.

[Fermentative production of 1,3;1,6-beta-D-glucan (translam), a labeled immunostimulant and investigation of its pharmacokinetics and pharmacodynamics].

Production of labeled translam from a marine mollusk was provided by the use 1,3-beta-D-glucanase. The pharmacokinetics of the 14C-translam metabolism in the experimental rats by the accumulation level and the retention time in the organs and tissue and the excretion rate with the feces and urine was of the same character as that of carbohydrates and in particular that of glucose, whereas the excretion of translam mainly with the urine was likely evident of its incomplete hydrolysis after the intramuscular administration.

[Efficiency of polysaccharide translam for early treatment of acute radiation illness]. / Effektivnost' polisakharida translama kak sredstva rannego lecheniia ostroi luchevoi bolezni.

Antiradiation therapeutic efficiency of translam (1-->3; 1-->6-beta-D-glucan) produced by enzymatic synthesis out of laminarin, polysaccharide of Laminaria cychorioides, has been studied in four animal species (mice, guinea-pigs, dogs, monkeys). A stable curative effect has been observed following its administration within first 24 h after radiation exposure at doses that cause acute radiation sickness (about LD90). The preparation is nontoxic and has a broad therapeutic range which permits its practical application.

[Feasibility of decreasing the adhesive activity of Corynebacterium diphtheriae by biopolymers of natural origin]. / Izuchenie vozmozhnosti snizheniia adgezivnoi aktivnosti Corynebacterium diphtheriae biopolimerami prirodnogo proiskhozhdneiia.

Possible decreasing of the Corynebacterium diphtheriae adhesive activity by natural biopolymers was studied. It was shown that the strains of C.diphtheriae circulating on the Primorye Territory had middle, low or minimal adhesive activity. Natural biopolymers were found to decrease the adhesive properties of C.diphtheriae. The results of the study are promising for further investigation of natural biopolymers as agents preventing C.diphtheriae colonization on the stomatopharynx mucosa.

[Determination and identification of beta-1,3;1,6-glycooligosaccharides in laminarioligosaccharide mixtures by means of enzymologic transglycosylation. Oligosaccharides with degree of polymerization of 5 and 6]. / Fermentativnoe transglikozilirovanie kak sposob obnaruzheniia i identifikatsii beta-1,3;1,6-gliukooligosakharidov v smesi laminarioligosakharidov. Oligosakharidy so stepen'iu polimerizatsii 5 i 6.

1-->3; 1-->6-beta-D-Glucooligosaccharides with polymerization degree of 5-6 were obtained from laminaran and analyzed by the previously developed method [1] by using them as donors and p-nitrophenyl beta-D-glucoside as the acceptor in the transglycosylation reaction catalysed by endo-1-->3-beta-D-glucanase LIV. The resulting homologous p-nitrophenyl beta-1,3-laminarioligosides with polymerization degree of 2-6 and the corresponding derivatives of mixed beta-1,3; 1,6-glucooligosaccharides with the same polymerization degree were analyzed by HPLC. The latter compounds exhibited higher retention times than the former with the same polymerization degree. Isomeric tetra-, penta-, and hexameric compounds were detected, and some of them were structurally characterized by means of NMR. The suggested method of analysis of oligosaccharide mixtures is simple, informative, and consumes a minimal quantity of sample.

[Synthesis of p-nitrophenyl laminarioligosides via transglycosylation reaction catalyzed by endo-1,3-beta-D- glucanase from marine mollusk]. / Poluchenie p-nitrofenil-laminarioligozidov reaktsiei transglikozilirovaniia, kataliziruemoi éndo-1,3-beta-d-gliukanazoi iz morskogo molliuska.

The transglycosylation reaction catalyzed by endo-1,3-beta-D-glucanase LIV from the marine mollusk Spisula sachalinensis was studied with the goal of preparing p-nitrophenyl (Np) 1,3- and 1,3; 1,6-D-glucooligosides. As donors we used the 1,3;1,6-beta-D-glucans with various content of beta-1, 6-glucoside bonds: laminarians [from Laminaria cichorioides (10%), L. gurjanovae (2%), and Fucus evanescens (35%)] and translam (25%); as acceptor we used the p-nitrophenyl beta-D-glucoside (GNp). The maximal yield of the transglycosylation products was found when using laminaran from Laminaria cichorioides; donors with a lower or higher content of beta-1,6-glucoside bonds were less efficient. The laminaran from F. evanescens and translam gave no Np-laminaribioside. At optimal conditions (10 mg/ml of laminaran from L. cichorioides and 5 mg/ml of GNp), maximal yields of Np-laminaribioside, Np-trioside, Np-tetraoside, and Np-pentaoside were 19, 8, 3, and 1%, respectively. The first two compounds were isolated by chromatography on silica gel, their physicochemical characteristics were obtained, and their structures were established by 13C NMR spectroscopy.

[The effect of translam on the immune response of irradiated mice]. / Vliianie translama na immunnyi otvet obluchennykh myshei.

Experimental facts about influence of new beta-1-3;1-6-glucan, extracted from seaweed Laminaria, on immune response of mice are summarized. The ability of translam to increase the number and functional activity of immunocompetent cells taking part in humoral immune response formation. The possibility of translam using for treatment and prophylaxis of radiation affections is discussed.

[Enzymatic conversion of laminaranes into 1-->3;1-->6-beta-D-glucans, possessing immunostimulating activity]. / Fermenativnoe prevrashchenie laminaranov v 1---3;1---6-beta-D-gliukany,obladaiushchie immunostimuliruiushchim deistviem.

A new 1-->3;1-->6-beta-D-glucan (translam) with immunostimulating activity was isolated from products of the laminaran (L. cichorioides) transformation with endo-1-->3-beta-D-glucanase L0 (Chlamys albidus). As compared with laminaran, translam has a higher molecular weight, contains a 2.5-fold number of 1-->6-bound glucose residues mainly about the nonreducing end of the molecule, but no mannitol. Some of the 1-->6-linked glucose residues are included, in contrast to laminaran in the main chain of 1-->3-beta-D-glucan. It was shown that the translam formation is due to the ability of endo-1-->3-beta-D-glucanase L0 to catalyze the synthesis not only of 1-->3-but also of 1-->6-glucosidic linkages.

[The effect of translam on the natural resistance indices of the irradiated organism]. / Vliianie translama na nekotorye pokazateli estestvennoi rezistentnosti obluchennogo organizma.

It has been studied the influence of translam-beta-1,3; 1,6-glucan, extracted from seaweed Laminaria, on the isolation of E. coli from spleen and on the functional activity of peritoneal macrophages of sublethal irradiated and infected mice. It has been shown the reduction of the number of microbes, isolated from spleen and stimulation of ingestive and digestive activity of macrophages following the introduction of translam in mice. This results show about the increase of natural resistance of irradiated organism under translam action and characterise this glucan as effective stimulator of immunity.

[Multiple attack in the mechanism of endoglucanase action]. / Iavlenie mnogokratnoi ataki v mekhanizme deistviia éndogliukanaz.

The review deals with the phenomenon of repetitive catalytic acts occurring in one enzyme-substrate encounter of certain endo-glucanases with water soluble polysaccharides. Here are discussed experimental results and theoretical models applied in analysis of data.

[Comparative study of laminarinases from marine mollusks using differential UV-spectrophotometry]. / Sravnitel'noe izuchenie laminarinaz iz morskikh molliuskov metodom raznostnoi UF-spektrofotometrii.

A comparative study of tryptophane residues in endo-beta-1.3-glucanases from marine molluscs was carried out by UV-differential spectrophotometry and chemical modification with N-bromosuccinimide methods. The number of tryptophane and tyrosine residues exposed and accessible to the solvent was determined, using a solvent perturbation technique with 20% ethylene glycol. The alteration in the accessibility of these residues in 8 M urea and in the presence of the reaction substrate was shown. The tryptophane residues of endo-beta-1.3-glucanases were found to participate in the enzyme-substrate interaction. The interaction between endo-beta-1.3-glucanases and the substrate, laminarine, as well as between the substrate analogs and inhibitors--cellobiose and glucone-1,5-lactone, was investigated.

[Endo-beta-1,3-glucanase using affinity inhibition]. / Issledovanie éndo-beta-1,3-gliukanazy metodom affinnogo ingibirovaniia.

Synthetic 2',3'-epoxypropyl-1-thio-beta-D-glucopyranoside selectively modifies a catalytically essential nucleophylic group in the active site of beta-1,3-glucanase LIV from the marine mollusc Spisula sachalinensis, the inactivation being as high as 95%. The properties of native and epoxypropylthioglucopyranoside-inhibited glucanase LIV were compared, using UV-spectroscopy, SDS polyacrylamide gel electrophoresis and isoelectrofocusing. It was found that the addition of laminarine and laminarioligosaccharides to a solution of the inhibited enzyme induces UV-differential spectra typical for the tryptophanyl residue involved in the formation of the enzyme-inhibitor-substrate complex. The glucone-1,5-lactone does not produce such spectrum. It was shown that epoxypropylthioglucopyranoside protects the accessible tryptophanyl residues in the enzyme active center against the oxidation by N-bromosuccinimide.

[Chemical modification of lysine residues of beta-1,3-glucanase from Spisula sachalinensis]. / Khimicheskaia modifikatsiia ostatkov lizina v beta-1,3-gliukanaze iz Spisula sachalinensis.

The effects of chemical modification of the amino groups of lysine residues on the activity of beta-1.3-glucanase from Spisula sachalinensis were studied. Modification of two lysine residues per molecule did not affect either the enzyme activity with respect to laminarine, nor the Km value. The modified beta-1.3-glucanase retains the ability to catalyze the transglycosylation and cleaves the high molecular weight CM-pachyman at the same rate as does the native enzyme. No significant changes in the enzyme thermal stability were observed. Thus, the modified enzyme groups cannot be involved in the enzyme active center and are exposed on the surface of the protein globule. The chemical modification was shown to have no effect on the enzyme kinetics, which is essential for its immobilization.

[1,3-beta-Glucanases of actinomycetes]. / 1,3-beta-Gliukanazy aktinomitsetov.

Different actinomyces species (25 strains) were studied and Actinomyces cellulosae 41 was found to be the most active one in its capacity to cause lysis of Saccharomyces cerevisiae intact cells as well as in the production of 1,3-beta-glucanase. The enzyme preparation containing 1,3-beta-glucanase can be obtained from the filtrate of the actinomycete cultural broth after 60 h of growth by precipitation with four volumes of ethanol. The optimal pH for the action of 1,3-beta-glucanase from A. cellulosae is 5.5. Hydrolysis of laminarin (5 mg of the substrate) yields 2.4 mg of reducing sugars or 13.3 microM (recalculated per glucose). There is a direct correlation between the amount of produced reducing sugars and the enzyme concentration up to 10 microM/ml (recalculated per glucose). The enzyme hydrolysate contains glucose and oligosaccharides with a different degree of polymerization. Therefore, the enzyme is endo-1,3-beta-glucanase. It produces less quantities of the disaccharide than those of glucose and trisaccharide. The enzyme yields only traces of glucose upon prolonged hydrolysis of p-nitrophenyl-beta-D-glucoside (PNPG) and shows a weak capacity for transglycosylation when laminarin is used as a donor and PNPG as an acceptor.

[Computer modeling of enzymatic hydrolysis of a linear polysaccharide by endoglycanases]. / Matematicheskoe modelirovanie fermentativnogo gidroliza lineinogo polisakharida éndoglikanazami.

The kinetics of linear polysaccharide hydrolysis with endoglycanases was studied with the help of computer modelling. Simple hydrolysis of a substrate (polymerization degree 30) -- analogous to beta-1,3-glucan -- laminarin was considered. The theoretical action patterns of several enzymes having active centres with known subsite maps were compared with experimental data for endolaminarinase LIV from Spisula sachalinensis. Analysis of the data obtained revealed some characteristic features in the course of the reaction and showed how to achieve information on the active centres of endoglycanases on the basis of such an action pattern. The method of evaluating maximum distance from the catalytic site to the boundary of the active centre was proposed.