Tag Archives: Aspergillus niger

Coordinative compounds of zinc with N-substituted thiоcаrbаmоil-N′-pentаmethylеnsulfenаmides – activity mоdifiers of еnzymes of proteolytic and glycolytic action

L. D. Varbanets1, Е. V. Mаtselyukh1, Е. V. Gudzenko1,
N. V. Bоrzоvа1, I. I. Sеifullina2, G. N. Khitrich2

1Zabolotny Institute of Microbiology and Virology, National Academy of Sciences of Ukraine, Kiev;
e-mail: varbanets@serv.imv.kiev.ua;
2Mechnikov Оdеssa National University, Ukraine

The influence of a number of coordinative compounds of zinc with N-substituted­ thiocarbamoil-N′-pentamethylensulfenamides on activity of elastase, α-L-rhamnosidase and α-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 α-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 α-L-rhamnosidase activity of Еupenicillium 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 α-galactosidases activity, however inhibited (up to 20%) activity of Penicillium canescens α-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.

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

N. V. Borzova, O. V. Gudzenko, L. D. Varbanets

Zabolotny Institute of Microbiology and Virology,
National Academy of Sciences of Ukraine, Kyiv;
e-mail: nv_borzova@bigmir.net

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.