THE INFLUENCE OF CITRATE SYNTHASE GENETIC BLOCK ON
METHANOL METABOLISM IN METHYLOTROPHIC YEST HANSENULA
POLYMORPHA
M. Gonchar
Division of Cell Regulatory Systems, O.V. Palladin Institute of Biochemistry, National
Academy of Sciences of Ukraine, 79005 L'viv, Drahomanov St. 14/16,
e-mail: gonchar@biochem.Lviv.ua
The glutamate-dependent mutants of H. polymorpha have been isolated. In five of them the activity of citrate synthase was completely absent. The mutants do not grow in the media with ethanol, glycerol or methanol as a sole source of carbon nutrition even in the presence of glutamate. One of the mutants devoid of citrate synthase (CS) also lacks alcohol oxidase (AO) activity. Glutamate-prototrophic temperature-sensitive-revertants possess thermolabile CS but still devoid of AO activity. It has been shown that oxidation of radioactive methanol to CO2 in CS deficient mutant is essentially repressed. The role of CS and tricarboxylic acid cycle in energetics of methylotrophic growth and possible functional relations between CS and AO are discussed.
Key words: citrate synthase, alcohol oxidase, energetics, methylotrophic yeast.
|