Biomaterial Database

Glucose repression of maltase and methanol-oxidizing enzymes in the methylotrophic yeast Hansenula polymorpha: isolation and study of regulatory mutants. 1998

T Alamäe, and L Liiv

Department of Genetics, University of Tartu, Estonia. talamae@ebc.ee

Regulation of the synthesis of maltase and methanol-oxidizing enzymes by the carbon source has been analyzed in the methylotrophic yeast Hansenula polymorpha. Maltase was shown to be responsible for the growth of H. polymorpha not only on maltose, but also on sucrose. The affinity of maltase towards maltase substrates decreased in the order: 4-nitrophenyl glucoside (PNPG) < sucrose < maltose. Mutants with glucose repression-insensitive synthesis of alcohol oxidase and maltase were obtained from H. polymorpha by mutagenesis and subsequent selection on methanol medium in the presence of 2-deoxy-D-glucose. One of the isolated mutants, L63, was studied in more detail. Mutant L63 was recessive and monogenic and it was not deficient in hexokinase. Its analysis revealed that H. polymorpha most probably has a repressor protein that in the presence of glucose can down-regulate expression of both maltase and enzymes of methanol oxidation.

UI	MeSH Term	Description	Entries
D010084	Oxidation-Reduction	A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).	Redox,Oxidation Reduction
D010843	Pichia	Yeast-like ascomycetous fungi of the family Saccharomycetaceae, order SACCHAROMYCETALES isolated from exuded tree sap.	Hansenula,Hansenulas,Pichias
D012097	Repressor Proteins	Proteins which maintain the transcriptional quiescence of specific GENES or OPERONS. Classical repressor proteins are DNA-binding proteins that are normally bound to the OPERATOR REGION of an operon, or the ENHANCER SEQUENCES of a gene until a signal occurs that causes their release.	Repressor Molecules,Transcriptional Silencing Factors,Proteins, Repressor,Silencing Factors, Transcriptional
D003470	Culture Media	Any liquid or solid preparation made specifically for the growth, storage, or transport of microorganisms or other types of cells. The variety of media that exist allow for the culturing of specific microorganisms and cell types, such as differential media, selective media, test media, and defined media. Solid media consist of liquid media that have been solidified with an agent such as AGAR or GELATIN.	Media, Culture
D004794	Enzyme Repression	The interference in synthesis of an enzyme due to the elevated level of an effector substance, usually a metabolite, whose presence would cause depression of the gene responsible for enzyme synthesis.	Repression, Enzyme
D005947	Glucose	A primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement.	Dextrose,Anhydrous Dextrose,D-Glucose,Glucose Monohydrate,Glucose, (DL)-Isomer,Glucose, (alpha-D)-Isomer,Glucose, (beta-D)-Isomer,D Glucose,Dextrose, Anhydrous,Monohydrate, Glucose
D000429	Alcohol Oxidoreductases	A subclass of enzymes which includes all dehydrogenases acting on primary and secondary alcohols as well as hemiacetals. They are further classified according to the acceptor which can be NAD+ or NADP+ (subclass 1.1.1), cytochrome (1.1.2), oxygen (1.1.3), quinone (1.1.5), or another acceptor (1.1.99).	Carbonyl Reductase,Ketone Reductase,Carbonyl Reductases,Ketone Reductases,Oxidoreductases, Alcohol,Reductase, Carbonyl,Reductase, Ketone,Reductases, Carbonyl,Reductases, Ketone
D000432	Methanol	A colorless, flammable liquid used in the manufacture of FORMALDEHYDE and ACETIC ACID, in chemical synthesis, antifreeze, and as a solvent. Ingestion of methanol is toxic and may cause blindness.	Alcohol, Methyl,Carbinol,Sodium Methoxide,Wood Alcohol,Alcohol, Wood,Methoxide, Sodium,Methyl Alcohol
D000520	alpha-Glucosidases	Enzymes that catalyze the exohydrolysis of 1,4-alpha-glucosidic linkages with release of alpha-glucose. Deficiency of alpha-1,4-glucosidase may cause GLYCOGEN STORAGE DISEASE TYPE II.	Acid Maltase,Lysosomal alpha-Glucosidase,Maltase,Maltases,Maltase-Glucoamylase,Neutral Maltase,Neutral alpha-Glucosidase,alpha-Glucosidase,Lysosomal alpha Glucosidase,Maltase Glucoamylase,Neutral alpha Glucosidase,alpha Glucosidase,alpha Glucosidases,alpha-Glucosidase, Lysosomal,alpha-Glucosidase, Neutral
D001426	Bacterial Proteins	Proteins found in any species of bacterium.	Bacterial Gene Products,Bacterial Gene Proteins,Gene Products, Bacterial,Bacterial Gene Product,Bacterial Gene Protein,Bacterial Protein,Gene Product, Bacterial,Gene Protein, Bacterial,Gene Proteins, Bacterial,Protein, Bacterial,Proteins, Bacterial