TY  - JA
AU  - Rozwadowski,K.L.
AU  - Khachatourians,G.G.
AU  - Selvaraj,G.
TI  - Choline, oxidase, a catabolic enzyme in Arthrobacter pascens, facilitates adaptation to osmotic stress in Escherichia coli
SN  - 0021-9193
U1  - 91-103384 
PY  - 1991///
KW  - Amines
KW  - Amino compounds
KW  - Ammonium compounds
KW  - Bacteria
KW  - Biochemical reactions
KW  - Biogenic amines
KW  - Cell structure
KW  - Chemical reactions
KW  - Chromosomes
KW  - Diffusion
KW  - Enzymes
KW  - Nucleus
KW  - Physical phenomena
KW  - quaternary ammonium compounds
KW  - Soil biology
N1  - references US (DNAL 448.3 J82)
N2  - Choline oxidase (EC 1.1.3.17) is a bifunctional enzyme that is capable of catalyzing glycine betaine biosynthesis from choline via betaine aldehyde. A gene (cox) encoding this enzyme in the gram-positive soil bacterium Arthrobacter pascens was isolated and characterized. This gene is contained within a 1.9-kb fragment that encodes a polypeptide of approximately 66 kDa. Transfer of this gene to an Escherichia coli mutant that is defective in betaine biosynthesis resulted in an osmotolerant phenotype. This phenotype was associated with the ability of the host to synthesize and assemble an enzymatically active choline oxidase that could catalyze biosynthesis of glycine betaine from an exogenous supply of choline. Although glycine betaine functions as an osmolyte in several different organisms, it was not found to have this role in A. pascens. Instead, both choline and glycine betaine were utilized as carbon sources. in A. pascens synthesis and activity of choline oxidase were modulated by carbon sources and were susceptible to catabolite repression. Thus, cox, a gene concerned with carbon utilization in A. pascens, was found to play a role in adaptation to an environmental stress in a heterologous organism. In addition to providing a possible means of manipulating osmotolerance in other organisms, the cox gene offers a model system for the study of choline oxidation, an important metabolic process in both procaryotes and eucaryotes
T2  - Journal of bacteriology (USA). (Jan 1991). v. 173(2) p. 472-478
ER  -