| Abstrakt: |
Hansenula polymorpha CBS 4732 was studied during cultivation on methanol and different glucose concentrations. Activities of Cu/Zn and Mn superoxide dismutase, catalase and methanol oxidase were investigated. During cultivation on methanol, increased superoxide dismutase and catalase activities and an induced methanol oxidase were achieved. Transfer of a methanol grown culture to medium with a high glucose concentration caused growth inhibition, low consumption of carbon, nitrogen and phosphate substrates, methanol oxidase inactivation as well as decrease of catalase activity (21.8 ± 0.61 ?E240× min -1× mg protein -1). At the same time, a high value for superoxide dismutase enzyme was found (42.9 ± 0.98 U × mg protein-1, 25% of which was represented by Mn superoxide dismutase and 75% - by the Cu/Zn type). During derepression methanol oxidase was negligible (0.005 ± 0.0001 U × mg protein -1), catalase tended to be the same as in the repressed culture, while superoxide dismutase activity increased considerably (63.67 ± 1.72 U × mg protein -1, 69% belonging to the Cu/Zn containing enzyme). Apparently, the cycle of growth inhibition and reactivation of Hansenula polymorpha CBS 4732 cells is strongly connected with the activity of the enzyme superoxide dismutase |
