[Component composition of Cryptococcus albidus and Eupenicillium erubescens alpha-L-rhamnosidases].

The component composition of Cryptococcus albidus and Eupenicillium erubescers alpha-L-rhamnosidases have studied. It was shown that enzymes have a monomeric structure. Enzyme preparations of C. albidus and E. erubescens have similar qualitative but differ in quantitative amino acid composition. alpha-L-rhamnosidase of C. albidus characterised by high amount of histidine, proline, cysteine, methionine in compared with alpha-L-rhamnosidase of E. erubescens. alpha-L-Rhamnosidase of E. erubescens, in contrast to the alpha-L-rhamnnosidase of C. albidus, contained higher levels of lysine, arginine, threonine, alanine, isoleucine, leucine, tyrosine, phenylalanine. It is shown that purified preparations of alpha-L-rhamnosidase C. albidus and E. erubescens contained 5 and 1% carbohydrates respectively. Enzyme preparations differ in quantitative monosaccharide composition, which represented by rhanmose, xylose, mannose, galactose and glucose. Furthermore, alpha-L-rhannosidase C. albidus contained fuicose, whereas alpha-L-rhamnosidase E. erubescens--ribose and arabinose. A significant percentage of hydrophobic amino acids, which is 31 and 34% of the total content, and the presence of the carbohydrate component are essential in stabilization of enzymes molecule.

[Hydrolytic activity of microorganisms of the Dead Sea coastal ecosystems].

All strains tested are characterized by proteolytic (caseinolytic) activity, while elastase one was revealed only in two Gracilibacillus strains 6T2 and 7Tl. The activity was high enough (23.1 and 34.7 E/Ml, respectively). These values are at the level of bacterial producers which are described in literature: Bacillus mesentericus 316 M (6 E/Ml), Bacillus thuringiensis IMB B-7324 (50-55 E/Ml). The ability of two strains tested to synthesize enzyme, active against elastine, is important, so far as microbial enzyme may be perspective for using in medicine: elastases are able to dissociation of elastin fibres of connective tissues. These two strains display also fibrinolytic activity, however it was insignificant. Six of eight strains studied manifested alpha-amylase activity (0.01 - 1.173 E/Ml). It was shown that no strains, isolated from the Dead Sea costal ecosystems are able to manifest alpha-L-rhamnosidase activity.

[Influence of coordination compounds of germanium (IV) and stannum (IV) on activity of some microbial enzymes with glycolytic and proteolytic action].

Influence of coordinative compounds of germanium (IV) and stanum (IV) (complexes of germanium (IV) with nicotinamide (Nad) [GeCl2(Nad)4]Cl2 (1) and complexes of stanum (IV) with 2-hydroxybenzoilhydrazone 4-dimetylaminobenzaldehide (2-OH-HBdb) [SnCl4(2-OH-Bdb-H)] (2), 3-hydroxy-2-naphtoilhydrazone 2-hydroxynaphtaldehide (3-OH-H2Lnf) [SnCl3(3-OH-HLnf)] (3) and izonicotinoilhydrazone 2-hydroxyibenzaldehide [SnCl3 (Is·H)] (4) on activity of peptidases 1 and 2 Bacillus thuringiensis, α-L-rhamnosidase Cryptococcus albidus, Eupenicillium erubescens and α-amylase Aspergillus flavus var. oryzae. Results testify that all studied compounds differ on their influence on activity of the enzymes tested: significantly don't change elastolytic activity of peptidases 1 and 2 B. thuringiensis, completely inhibit A. flavus var. oryzae amylase, activate or oppress of α-L-rhamnosidase C. albidus and E. erubescens. Considerable differences in compounds (3, 4) on activity observed in case of the last. It's possible that peculiarity of influence (1) in compare with (2-4) is connected with existence of different central atoms of complexants: germanium (IV) (1) and stanum (IV) (2-4). A certain analogy in oppression of C. albidus α-L-rhamnosidase by compounds (1) and (4) can explain with presence of a pyridinic ring at molecules of their ligands. The less activsty displayed compound (2) with coordinative knot {SnCl4ON}. Nature of compounds (3, 4) activity was absolutely different: essential increase of activity of C. albidus α-L-rhamnosidase and full oppression of E. erubescens α-L-rhamnosidase by compound (3), while the action of compound (4) was feed back. Taking into account identical coordination knot {SnCl3O2N} the major role in this case play change of a hydrazide fragment in molecules of their ligands.

[Substrate specificity of Cryptococcus albidus and Eupenicillium erubescens alpha-L-rhamnosidases].

The substrate specificity of Cryptococcus albidus and Eupenicillium erubescens alpha-L-rhamnosidases has been investigated. It is shown that the enzymes are able to act on synthetic and natural substrates, such as naringin, neohesperidin. alpha-L-Rhamnosidases hydrolysed the latter ones very efficiently, in this case E. erubescens enzyme was characterized by higher values of V(max) in comparison with the enzyme of C. albidus. However the C. albidus alpha-L-rhamnosidase showed greater affinity for naringin and neohesperidin than the enzyme of E. erubescens (K(m) 0.77 and 3.3 mM and 5.0 and 3.0 mM, respectively). As regards the synthetic derivatives of monosaccharides, both enzymes exhibited narrow specificity for glycon: E. erubescens alpha-L-rhamnosidase--only to the p-nitrophenyl-alpha-L-rhamnopiranoside (K(m) 1.0 mM, V(max) 120 micromol/min/mg protein), and C. albidus--to p-nitrophenyl-alpha-D-glucopyranoside (K(m) 10 mM, V(max) 5 micromol/min/mg protein). Thus, it was found that the enzyme preparations of E. erubescens and C. albidus are differed by their substrate specificity. The ability of E. erubescens and C. albidus alpha-L-rhamnosidases to hydrolyse natural substrates: naringin and neohesperidin, evidences for their specificity for alpha-1,2-linked L-rhamnose. Based on these data, we can predict the use of E. erubescens and C. albidus alpha-L-rhamnosidases in various industries, food industry in particular. This is also confirmed by the fact that the investigated alpha-L-rhamnosidases were stable at 20% concentration of ethanol and 500 mM glucose in the reaction mixture.

[Optimization of cultivation conditions of Cryptococcus albidus--producers of alpha-L-rhamnosidase].

The influence of content of cultivation media and fermentation conditions on synthesis of alpha-L-rhamnosidase by Cryptococcus albidus 1001 and 1003 were studied. It was shown that L-rhamnose and NaNO, are the optimum sources of carbon and nitrogen, respectively. The temperature of 25 degrees C, pH 6.0, growing in 50 ml of the medium at rotation rate 220 rev/min during 6 days are optimum parameters for both strains.

[Alpha-amylases of Bacillus subtilis].

Preparations of alpha-amylase have been obtained as a result of screening of Bacillus subtilis strains. They can hydrolyse starch at a temperature from 60 to 95 degrees C at acidic and alkaline values of pH and hold stability during 2-3 hours. Alpha-Amylase of B. subtilis 147 with optimum pH 9.1 which displayed activity at 95 degrees C, proved to be promising for further investigations, since it is competitive with the already described alpha-amylases of Bacillus.