## Electronic Theses and Dissertations

1990

Dissertation

Ph.D.

#### Department

Chemistry and Biochemistry

#### Keywords

Chemistry, Biochemistry.

CC BY-NC-ND 4.0

#### Abstract

Following a 24 h incubation of glucose-grown whole cells of Pseudomonas putida with D- (U-$\sp{14}$C) 4-deoxy-4-fluoro-D-glucose (4FG), there is an extensive release of fluoride ion, (95 $\pm$ 5%). The isolated peptidoglycan (PG) fraction contains less than 1% of the radiolabel. This small, but significant amount of radioactivity is not due to the presence of a novel carbohydrate derived from 4FG. HPLC analysis with an Aminex HPX-87C (Bio-Rad) carbohydrate analytical column reveals the presence of the radioactive amino acids threonine, serine, glutamate and aspartate. These are considered to have arisen from the observed $\sp{14}$CO$\sb2$ from 4FG. When the incubation is performed with NaH$\sp{14}$CO$\sb3$ an identical isolation and analysis of the PG shows the presence of radioactive N-acetylglucosamine, muramic acid, glucosamine, glutamate and aspartate. Pathways for $\sp{14}$CO$\sb2$ incorporation into PG are presented. Preparative scale isolation of a previously unknown minor metabolite resulting from a 24 h incubation of P. putida and 4FG reveals the $\gamma$-lactone of 2,3-dideoxy-D-glycero-pentonic acid. Metabolic studies suggest that a chemiosmotic energy couple ($\Delta$ pH) is required for the defluorination of 4FG, which is not dependent upon ATP synthesis. These studies suggest the possibility that a periplasmic shock-resistant biding protein could be implicated in the mechanism of fluoride release. Time course studies reveal that within the first 80 min of incubation of D- (U-$\sp{14}$C) 4FG with P. putida, the removal of 4FG from the suspending medium is concomitant with the appearance of a non-fluorinated intermediate metabolite in the supernatant. NMR and mass spectrometry data suggest the structure of 4-deoxy-5-keto-D-glucose and/or 4-deoxy-D-glucose. An examination of the intracellular contents of P. putida over the same time profile reveals the presence of 4FG and an unknown metabolite. The site, possible mechanism of defluorination of 4FG and its subsequent metabolism to 2,3-dideoxy-D-glycero-pentonic acid are discussed in relation to glucose transport and metabolism in pseudomonads.Dept. of Chemistry and Biochemistry. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1990 .W555. Source: Dissertation Abstracts International, Volume: 52-11, Section: B, page: 5810. Thesis (Ph.D.)--University of Windsor (Canada), 1990.

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