ISSN:
1432-072X
Keywords:
Derepression
;
Catabolite inactivation
;
Alcohol oxidase
;
Catalase
;
Formaldehyde dehydrogenase
;
Formate dehydrogenase
;
Hansenula polymorpha
;
Kloeckera sp. 2201
;
Peroxisomes
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract The regulation of the synthesis of four dissimilatory enzymes involved in methanol metabolism, namely alcohol oxidase, formaldehyde dehydrogenase, formate dehydrogenase and catalase was investigated in the yeasts Hansenula polymorpha and Kloeckera sp. 2201. Enzyme profiles in cell-free extracts of the two organisms grown under glucose limitation at various dilution rates, suggested that the synthesis of these enzymes is controlled by derepression — represion rather than by induction — repression. Except for alcohol oxidase, the extent to which catabolite repression of the catabolic enzymes was relieved at low dilution rates was similar in both organisms. In Hansenula polymorpha the level of alcohol oxidase in the cells gradually increased with decreasing dilution rate, whilst in Kloeckera sp. 2201 derepression of alcohol oxidase synthesis was only observed at dilution rates below 0.10 h−1 and occurred to a much smaller extent than in Hansenula polymorpha. Derepression of alcohol oxidase and catalase in cells of Hansenula polymorpha was accompanied by synthesis of peroxisomes. Moreover, peroxisomes were degraded with a concurrent loss of alcohol oxidase and catalase activities when excess glucose was introduced into the culture. This process of catabolite inactivation of peroxisomal enzymes did not affect cytoplasmic formaldehyde dehydrogenase.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00427715
