Date of Award

1983

Degree Type

Dissertation

Degree Name

Ph.D.

Department

Chemistry and Biochemistry

Keywords

Chemistry, Biochemistry.

Rights

CC BY-NC-ND 4.0

Abstract

Glucose grown whole cells of Pseudomonas putida do not oxidize 4-deoxy-4-fluoro-D-glucose (4FG). Instead, an extensive release of fluoride ion occurs in which no defluorinated sugar could be detected. Cytoplasmic membrane vesicles and cell-free extracts from this organism oxidize 4FG to the extent of 1 mol oxygen mol substrate('-1) with retention of the carbon-fluorine bond. The defluorination reaction displays saturation kinetics with an apparent K(,m) of 3.9 mM and an apparent V(,max) of 1 nmol fluoride mg protein('-1) min('-1). The reaction is inhibited in the presence of glucose, gluconate or 2-ketogluconate. Growth of cells on gluconate or 2-ketogluconate does not affect the rate of extent of fluoride release from 4FG. On the other hand, cells grown on succinate or citrate have drastically reduced rates and extents of fluoride release, demonstrating that defluorination of 4FG is dependent upon the presence of protein. Pre-incubation of P. putida with chloramphenicol further demonstrates the presence and synthesis of protein responsible for the defluorination of 4FG. Fractionation of whole cells indicates that the probable site of the defluorinating protein is in the outer membrane. Treatment of whole cells with D-{6-('3)H}-4-deoxy-4-fluoroglucose results in the formation of a radiolabeled peptidoglycan-associated protein located in the outer membrane fraction. The molecular weight of this covalently glycosylated protein is estimated to be 40,000 by column chromatography. The results obtained in this investigation are discussed in relation to the mechanism of glucose transport in whole cells of P. putida and other pseudomonads. Source: Dissertation Abstracts International, Volume: 44-09, Section: B, page: 2732. Thesis (Ph.D.)--University of Windsor (Canada), 1983.

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