[Screening of Mannane-Degrading Enzymes Producers].

The aim of research was to investigate the prevalence of complex mannan-degrading enzymes among museum and freshly isolated cultures of micromycetes, actinobacteria and bacteria. It has been shown that the producers of ß-mannanases mostly extracted from sources that are rich in plant residues. We detected strains of Penicillium aculeatum, P. tardum and P. rugulosum which produce a complex of ß-mannanases and α-galactosidase activity. Also, strains of thermophilic micromycetes species Corynascus sepedonium, Scytalidium thermophilum and Rhizomucor tauricus with high mannanase activity in culture liquid were detected (10 ­ 130 U/ml). Two strains of P. aculeatum and P. tardum showed ß-mannanase, ß-mannosidase and α-galactosidase activity. Actinobacteria was shown high potential, 70 % of all tested strains showed mannanase activity; their activity ranged from 2 to 55 U/ml. Among the most active bacterial cultures were representatives of soil microflora: Bacillus circulans, B. subtilis, B. mesentericus, where as among the strains isolated from sea water the active mannanases producers were not found.

STABILITY OF NATIVE AND MODIFIED α-GALACTOSIDASE OF Cladosporium cladosporioides.

By modifying carbohydrate component of glycoproteins it is possible to elucidate its role in manifestation of structural and functional properties of the enzyme. The comparison of activity and stability of the native and modified by oxidation with sodium periodate α-galactosidase of Cladosporium cladosporioides was carried out. To determine α-galactosidase activity the authors used n-nitrophenyl synthetic substrate, as well as melibiose; raffinose and stachyose. Modification of the carbohydrate component had a significant effect on catalytic properties of the enzyme. Both the reduction of V and enzyme affinity for natural and synthetic substrates were observed The native enzyme retained more than 50% ofthe maximum activity in the range of 20-60 °C, while for the modified enzyme under the same conditions that temperature range was 30-50 °C. The modified α-galactosidase demonstrated a higher thermal stability under neutral pH conditions. The residual activity of the modified α-galactosidase was about 30% when treated with 70% (v/v) methanol, ethanol and propanol. About 50% of initial activity was observed when 40% ethanol and propanol, and 50% methanol were used. It was shown that the modification of C. cladosporioides α-galactosidase by sodium periodate is accompanied by a significant decrease in enzyme activity and stability, probably caused by topological changes in the tertiary and quaternary structure of the protein molecule.

THERMAL STABILITY OF Cryptococcus albidus α-L-RHAMNOSIDASE.

Yeast as well as micromycetes α-L-rhamnosidases, currently, are the most promising group of enzymes. Improving of the thermal stability of the enzyme preparation are especially important studies. Increase in stability and efficiency of substrate hydrolysis by α-L-rhamnosidase will improve the production technology of juices and wines. The aim of our study was to investigate the rate of naringin hydrolysis by α-L-rhamnosidase from Cryptococcus albidus, and also some aspects of the thermal denaturation and stabilization of this enzyme. We investigated two forms of α-L-rhamnosidase from C. albidus, which were obtained by cultivation of the producer on two carbon sources--naringin and rhamnose. A comparative study of properties and the process of thermal inactivation of α-L-rhamnosidases showed that the inducer of synthesis had no effect on the efficiency of naringin hydrolysis by the enzyme, but modified thermal stability of the protein molecule. Hydrophobic interactions and the cysteine residues are involved in maintaining of active conformation of the α-L-rhamnosidase molecule. Yeast α-L-rhamnosidase is also stabilized by 0.5% bovine serum albumin and 0.25% glutaraldehyde.

Role of glycosylation in secretion and stability of micromycetes α-galactosidase.

The effect of the glycosylation inhibitors (tunicamycin and 2-deoxy-D-glucose) on the activity, stability and production of fungal glycosidases has been studied. It was shown that inhibition of N-glycosylation sites did not affect the secretion of Aspergillus niger α-galactosidase, however reduced yield of Cladosporium cladosporioides and Penicillium canescens α-galactosidases. Changes in the level of O-glycosylation resulted in a significant reduction in the activity and stability of α-galactosidases of all three producers tested. Activity of the modified enzymes was significantly lower than that of the native ones, and was 2.6 and 0.33 U/mg for A. niger α-galactosidase, 3.3 and 32.5 U/mg for C. cladosporioides α-galactosidase, 11.66 and 31.1 U/mg for P. canescens α-galactosidase, respectively. A. niger α-galactosidase completely lost activity during purification and storage. The decrease of thermal stability at 55 °C by 20% was shown for C. cladosporioides and P. canescens α-galactosidases. It was also noted that O-deglycosylation led to a decrease in resistance of these enzymes to the action of proteases.

[Influence of metal ions and specific chemical reagents on activity of alpha-L-rhamnosidase of Eupenicillium erubescens].

The effect of cations, anions and specific chemical reagents: 1-[3-(dimethylamino) propyl]-3-ethylcarbodiimide methiodide, EDTA, o-phenanthroline, dithiotreitol, L-cysteine, beta-mercaptoethanol, p-chlormercurybenzoate (p-ChMB), N-ethylmaleimide on the activity of alpha-L-rhamnosidase of Eupenicillium erubescens has been investigated. The essential role of Ag+ and Hg2+ which inhibit the alpha-L-rhamnosidase activity by 47-73% has been shown. Whereas L-cysteine exhibits the protective effect, rhamnose in concentration of 1-5 mM does not protect the enzyme from negative effect of Ag+ and Hg2+. Basing on the inhibitory and kinetic analysis it was supposed that the carboxyl group of C-terminal aminoacid and imidazole group of histidine take part in the catalytic action of alpha-L-rhamnosidase. It was assumed that sulphydryl groups took part in catalysis, carried out by alpha-L-rhamnosidase of E. erubescens, since the activity of alpha-L-rhamnosidase inhibited by p-ChMB and thiol reagents such as dithiothreitol, L-cysteine, beta-mercaptoethanol did not remove its inhibitory action.

[The Black Sea bacteria--producers of hydrolytic enzymes].

Investigation of 15 different glycoside activities of 64 strains isolated from water and invertebra of the Black Sea has shown that 64% of the studied strains displayed the capacity to synthesize enzymes with alpha-L-ramnosidase activity which varied from 0.01 to 0.20 un/ml depending on the strain. The greatest number of the enzyme producers was found in representatives of Alteromonas macleodii. Other investigated glycosidase activities: alpha-amylase, beta-N-acetyl-D-glucosaminidase, beta-D-glucuronide, alpha-N-acetyl-D-galactosaminidase, beta-N-acetyl-D-galactosaminidase, beta-D-galactosidase, alpha-D-galactosidase, beta-D-glucosidase, KM-cellulase activities though have been found, but mainly with inconsiderable indices, alpha-D-glucosidase, alpha-D-mannosidase, alpha-L-fucosidase, beta-D-xylosidase and alpha-D-xylosidase activities were found in neither of the studied strains. Strains with rather high proteolytic activity were found among marine species of bacteria. It has been established that 18 strains (28%) of 64 marine isolates were characterized by rather high level of total proteolytic activity (from 0.1 to 05 un/ml), 43.75% of them displayed inconsiderable (up to 0.1 un/ml) or only trace (up to 0.01 un/ml), 18.75% did not display any hydrolytic activity in respect of casein. Investigation of substrate specificity to a number of fibrillar and globular proteins of 9 studied strains, which displayed considerable general (caseinolytic) activity has shown that 8 of them displayed fibrinolytic activity from 0.15 to 2.175 un/ml. All 9 strains were characterized by gelatin activity. Collagenase and keratinase activity was also revealed. Neither of 9 studied strains displayed elastase activity.

[Coordinative compounds of zinc with N-substituted thiocarbamoyl-N'-pentamethylensulfenamides--activity modifiers of enzymes of proteolytic and glycolytic action].

The influence of a number of coordinative compounds of zinc with N-substituted thiocarbamoil-N'-pentamethylensulfenamides on activity of elastase, alpha-L-rhamnosidase and alpha-galactosidases evidence for a possibility of their usage as stimulators or inhibitors of enzymes tested have been studied. It was shown that all the compounds in concentration of 0.1 and 0.01% inhibited by 90-100% Bacillus thuringiensis 27-88Els+ elastase activity. [Zn(L2)Br2], [Zn(L1)(NCS)2] and [Zn(L3)(NCS)2] at 20 h exposition activated Cryptococcus albidus 1001 alpha-L-rhamnosidase activity. The rest of compounds influenced it on the control level or inhibited it by 7-23%. The obtained results testify that essential role is not played by separate fragments (L-ligand and anions), but by molecules of zinc complexes as a whole. All the studied complexes, exept for [Zn(L3)(NCS)2], induced alpha-L-rhamnosidase activity of Eupenicillium erubescens 248 (7 to 60%). All zinc compounds (concentration 0.01%, exposition time - 60 min) influenced at the control level Aspergillus niger and Cladosporium cladosporioides alpha-galactosidases activity, however inhibited (up to 20%) activity of Penicillium canescens alpha-galactosidase. The increasing of exposition time of the compounds tested with enzymes up to 20 h testify to selective action of separate compounds on enzymes tested. The data obtained prove, that the character of interaction of zinc complexes is changed depending on the enzyme tested and its strain-producer.

[Optimization of cultivation conditions of alpha-L-rhamnosidases producers-- representatives of different taxonomic groups of microorganisms].

Influence ofsome technological parameters of cultivation ofproducers Cryptococcus albidus, Eupenicillinum erubescens, Bacillus sp. on the process of synthesis of extracellular enzyme alpha-L-rhamnosidase has been studied. The authors have determined optimal sources of carbon (0.2-0.3% rhamnose) and nitrogen (0.2% sodium nitrate for C. albidus and E. erubescens and ammonium sulphate for Bacillus sp.) (the ratio 1:2), cultivation temperature (28 degrees C, 25 degrees C, 42 degrees C, respectively) for maximum synthesis of alpha-L-rhamnosidase. Use of the medium with initial pH value from 4 to 8 was most efficient for all the studied strains. The maximum level of alpha-L-rhamnosidase activity of E. erubescens and Bacillus sp. was established at the value of sulphite number of 0.44, while for C. albidus--it was 0.56. Maximum alpha-L-rhamnosidase activity of C. albidus, E. erubescens, Bacillus sp. is achieved at 4, 8 days and 27 hours of cultivation, respectively. The cultures being grown in selected conditions, the alpha-L-rhamnosidase synthesis has increased by 30, 50 and 20%, respectively.

[Thermal inactivation of alpha-galactosidase from Penicillium canescens].

The kinetics and mechanism of thermal inactivation of Penicillium canescens alpha-galactosidase in the temperature range of 55-65 degrees C have been studied. The kinetic scheme of alpha-galactosidase thermal inactivation was proposed which included the reversible dissociation of active hexamers into associating monomers and irreversible denaturation of monomers. The kinetic constants of thermal inactivation have been determined. The effect of enzyme concentration and purification efficiency has been investigated. A possibility of defence of protein molecule from thermal inactivation in the presence of BSA, glycerol, melibiose, raffinose and stachyose is shown.

[Characteristics of Aspergillus sp. 55 alpha-amylase].

The influence of different factors on biosynthesis of extracellular alpha-amylase of Aspergillus sp. 55 grown at submerged cultivation has been studied. The optimal composition of nutrient medium (1 g of starch and 0.5 g of NaNO3 per 1 l) was chosen. The enzyme preparation has a wide pH optimum of activity (4.5-9.0), thermooptimum at pH 6.5 was 60 degrees C, at pH 4.5 and 9.0--50 degrees C. The inhibitory effect of coordinative germanium compounds on amylolytic activity of the preparation was shown. The paper is presented in Ukrainian.

[Mannanases of microorganisms].

The current data on microbial mannanases are summarised in the work. The questions concerning the spreading of mannanases substrates--mannans in nature, their structural variations are regarded. The production of mannanases by micro-organisms of different taxonomic groups, their physico-chemical properties and substrate specificity are described. The ways of mannans hydrolysis by mannanase are estimated. The questions of cloning and expression of mannanase genes have been discussed. These results are very important for producing highly effective microbial biosynthetics.

[Regression of left ventricular hypertrophy and improvement of its diastolic function in patients with arterial hypertension under influence of antihypertensive therapy].

Antihypertensive therapy with sequential addition of drugs (noliprel, noliprel-forte, metoprolol, amlodipine) for achievement of target blood pressure (BP) below 140/90 mm Hg was used in the treatment of 99 patients with arterial hypertension (AH) with (n=51) or without left ventricular (LV) hypertrophy (LVH). At initial Doppler study of transmitral blood flow all patient with LVH had type 1 (n=48) or type 2 (n=3) diastolic LV dysfunction. Among patients without LVH 13 had minor type 1 diastolic LV dysfunction. After 12 - 14 months of antihypertensive therapy in all 44 patients with moderate LVH (myocardial mass index below 140 g/m2) BP corresponded to target level. This was associated with 6% decrease of myocardial mass index (MMI) and its normalization in 2/3 of patients, restoration of diastolic function in 3/4 of patients and its improvement in other patients, decrease of functional class, in rease of 6 min walking distance, and improvement of quality of life according to questionnaire for patients with CHF. In 7 patients with pronounced LVH (MMI 140 g/m2) target BP was not achieved, LVMMI, diastolic function, and functional class did not change, however tolerance to physical effort and quality of life improved. Thus in all patients with AH without LVH target BP level was achieved. In minor initial diastolic dysfunction diastolic function restored to normality, functional class, tolerance to physical work and quality of life improved.

[Investigations of functional groups of Penicillium commune 266 alpha-L-rhamnosidases].

On the basis of the data of metal ions influence it was established that Penicillium commune 266 alpha-L-rhamnosidases are dependent of metals. The cations of Cu2+, Mn2+, Ag+, Hg2+ essentially influenced the activity decreasing its up to 45-55%. Ba2+ and Mn2+ ions completely inhibited alpha-L-rhamnosidase 2 activity in concentration of 10(-3) M. The role of carboxylic group and histidine imidazole group in hydrolysis of rhamnoglycosides have been estimated by the Dixon, Lineweaver-Burke and photooxidation methods. It was also shown that sulfhydrilic groups which do not take part in catalysis, but are necessary for displaying the enzymatic activity are located at a certain distance from P. commune 266 alpha-L-rhamnosidase active centre.

[Aspergillus niger alpha-N-acetylgalactosaminidase: isolation, purification and properties].

alpha-N-acetylgalactosaminidase has been isolated from liquid culture of micromycete Aspergillus niger and purified 600 times by ammonium sulphate precipitation followed by ion exchange and gel-filtration chromatography on TSK-gels with specific activity 10.5 U/mg of protein. The preparation was homogenic: its molecular mass by the data of gel-filtration on Sepharose 6B was 430 kDa, on PAAGE in the system of DDSNa--70 kDa. That gives every reason to suppose oligomeric structure of the enzyme molecule. The carbohydrate component, including mannose, galactose, glucosamine and two nonidentified hexosamines was observed in alpha-N-acetylgalactosaminidase. Thermo- and pH- optima were 60 degrees C and pH 3.5, respectively. The enzyme was thermo- and pH-stable, resistant in storage. The enzyme was found to exhibit strict specificity in respect ofglycon. It was shown that enzyme was competitively inhibited by substrate and reaction product. Km and Vmax with respect to nitrophenyl substrate were 1.25 mM and 10.5 mkmole/min/mg of protein. The activity of glycosidase tested was independent of the presence of metal ions. The presence of carboxylic group of C-terminal aminoacid and imidazol group of hystidine in active centre of molecule was established. A number of natural and synthetic substrates were able to activate (50-200%) production of A. niger alpha-N-acetylgalactosaminidase.

[Kinetic characteristics of glycosidases of Aspergillus niger 185III].

It was established, as a result of investigation of kinetic properties of two fungal glycosidases (alpha-N-acetylgalactosaminidase and alpha- galactosidase), that Km and Vmax for the corresponding synthetic substrates were 1.19 and 1.25 mM, 25.0 and 10.5 micromol/min/mg of protein, respectively. a-Galactosidase and alpha-N-acetylgalactosaminidase were also competitively inhibited by the reaction products - D-galactose and N-acetylgalactosamine, the inhibition constants were 8.5 x 10(-3) and 6.2 x 10(-2) M, respectively. One could also observe the inhibition of alpha-galactosidase reaction in the presence of 10(-3) M of fucose, lactose and arabinose. It was shown that the rate of enzymatic hydrolysis of nitrophenyl substrates was directly proportional to the concentration of enzymes, and the increase of the substrate concentration leads to the increase of hydrolysis rate. The substrate concentration being increased above the optimal one (3.6 mg/ml), the decrease of the reaction rate owing to the formation of inactive enzyme-substrate complex FS2 may be observed.

[Substrate specificity and action mechanism of glycosidases].

Result of author's research and data from literature have been generalized with respect to hydrolase and transferase activity of glycosidases: alpha-galactosidase and alpha-N-acetylgalactosaminidase--the enzymes which catalyse hydrolysis of natural and synthetic glycosides. Broad variability of action specificity of glycosidases with respect to glycon, aglycon as well as the bond type depending on the enzyme isolation source have been shown. One can suppose that the enzyme action specificity is connected with different formation mechanisms of enzyme-substrate complexes. An idea is discussed concerning the identity of the mechanism of splitting of various glycosidic links by the studied enzymes.

[Screening of microorganisms--producers of alpha-L-rhamnosidase].

Screening of producers of alpha-L-rhamnosidase among 692 strains of microorganisms of different taxonomic groups has been performed. A capacity to synthesize the enzyme was revealed in 35.7% of the studied cultures. Representatives of genera Aspergillus, Myrothecium, Penicillium, Eupenicillium (activity 0.1 - 0.335 un./mg of protein) proved to be the most active producers. Complex preparations of alpha-L-rhamnosidase were obtained from cultural liquid of 10 producers by fractionation with ammonium sulfate (30 and 90% saturation); pH- and thermal optimum, as well as pH- and thermostability were analyzed in 7 of them. The Aspergillus, Penicillium, Eupenicillium strains which display high stability and activity under technological values of temperature 20-37 degrees C and medium pH 4.0-6.0 have been chosen for further investigations.

[Study of the topology of the active center of glycosidases of Aspergillus niger]. / Doslidzhennia topolohiï aktyvnoho tsentru hlikozydaz Aspergillus niger.

Activity of alpha-N-acetylgalactosaminidase and alpha-galactosidase isolated from the culture medium of micromycete Aspergillus niger v. Tiegh F-16694 has been studied as affected by anions, cations and specific chemical reagents (n-chlormercurybenzoate, L-cysteine, dithiotreitol, beta-mercaptoethanol, EDTA, o-phenanthroline, sodium azide, hydrogen peroxide). It has been established that silver ions noncompetitively inhibit alpha-galactosidase at pH 5.2, the inhibition constant (Ki) being 2.5 x 10(-4) M. Galactose in concentration of 1-5 mM does not protect the enzyme from the negative action of silver ions, but this inhibitory effect is almost completely removed by the corresponding concentrations of L-cysteine. The same noncompetitive character was inherent in the inhibition of alpha-galactosidase reaction by mercury ions and n-chlormercurybenzoat (Ki is 4.5 x 10(-6) and 1.8 x 10(-4), respectively). The importance of sulphydryl groups for the support of active comformation of alpha-galactosidase molecule was established on the basis of inhibition and kinetic analysis. It has been shown that the enzyme molecule does not contain the groups which include metal atoms.

[Purification and physico-chemical properties of glycosidase of Aspergillus niger 185sh]. / Ochystka ta fizyko-khimichni vlastyvosti glikozydazy Aspergillus niger 185sh.

A scheme has been developed for isolation and purification of the enzyme with alpha-N-acetylgalactosaminidase and alpha-galactosidase activities which included fractionation by ammonium sulphate and chromatography on TSK-gels Toyopearl HW-60 and Fractogel DEAE-650-s and Sepharose 6B. The enzyme was purified 600 times with the yield of 28%. The enzyme preparation did not contain fucosidase, invertase and proteolytic activities. Molecular mass of the enzyme from the data of gel-filtration on Sepharose 6B was 430 kDa, according to the data of electrophoresis in DS-PAAG--70 kDa. It is shown that acidic and hydrophobic aminoacids prevail in the enzyme molecule, the carbohydrate component containing galactose, mannose, glucosamine and two nonidentified hexosamines is also present there. The enzyme preparation is stable during 48 hours at 20 degrees C; its pH-optimum is at pH 3.5-4.1. Michaelis constants concerning n-nitrophenyl-alpha-N-acetylgalactopyranoside and n-nitrophenyl-alpha-D-galactopyranoside were 1.18 and 1.25 mM, respectively.

[Effect of coordinational germanium compounds on enzyme synthesis and activity]. / Vliianie koordinatsionnykh soedinenii germaniia na sintez i aktivnost' fermentov.

Germanium complexes (IV) with succinic (H2Suc), oxyethyliminodiacetic (H2Oeida) and iminodisuccinic (H4Ids) acids as well as homo- and heteroligand germanium complexes (IV)--products of interaction of triammonium salt of oxyethylidendiphosphonic acid ((NH4)3HL) and oxyacids: tartaric (H4Tart), citric (H4Citr), trioxyglutaric (H4Toglut) acids have been synthesized. Composition of the obtained complexes: [Ge(OH)2(NaSuc)2].2H2O (I); [Ge(OH) (Oeida).H2O].H2O (II); [Ge(OH)2(NaHIds)2] (III); [Ge(OH)2(NH4)3HL) (H2Tart)] (IV); [Ge(OH)2(NH4)3HL) (H2Citr)] (V); [Ge(OH)2(NH4)3HL) (H2Toglut)] (VI); [Ge(OH)2((NH4)2HL)2] (VII); [Ge (OH)2((NH4)2HL)2] (VII); [Ge(OH)2 (H2O)2(NH4) HL] (VIII) has been determined. The capability of the synthesized compounds has been studied to affect synthesis and activity of the following enzymes: collagenase, alpha-N-acetylgalactosaminidase (alpha-GalNAc-ase) and alpha-galactosidase (alpha-Gal-ase). It has been established that the complexes II-VIII activate biosynthesis of alpha-Gal-ase and alpha-GalNAc-ase, while germanium dioxide (IX) and complex I possess considerable inhibiting effect on synthesis of the above enzymes. It has been also established that all the compounds except for IV increased the activity of both alpha-Gal-ase and alpha-GalNAc-ase. All the considered complexes demonstrated similar reaction with respect to collagenase: they inhibited both synthesis and activity.