Accession Number : AD0617467

Title :   MUTANT OF SALMONELLA TYPHIMURIUM DEFICIENT IN THE CARBON DIOXIDE-FIXING ENZYME PHOSPHOENOLPYRUVIC CARBOXYLASE,

Corporate Author : PENNSYLVANIA UNIV PHILADELPHIA

Personal Author(s) : Theodore,Theodore S. ; Englesberg,Ellis

Report Date : 18 MAY 1964

Pagination or Media Count : 10

Abstract : Resting cells of Salmonella typhimurium wild type (C+dg8) and the C-dg8 mutant characterized by impaired glucose and glycerol metabolism are able to oxidize Krebs cycle intermediates to the same extent. The wild type oxidized glucose and pyruvate completely, and the mutant oxidized these substrates at a reduced rate and incompletely, with the accumulation of acetate. Resting cells of the wild type in the presence of NaHCO3-C14 and glucose incorporated 11 times more CO2 than did similar suspensions of the mutant. Extracts prepared from cells previously grown in a mineral glucose supplemented medium revealed that the mutant was deficient in the CO2-fixing enzyme phosphoenolpyruvic carboxylase (PEP carboxylase). This enzyme was found to be present in the wild-type extracts. It catalyzes the formation of oxaloacetate from phosphoenolpyruvate and CO2 in the presence of Mn(++) or Mg(++). No added nucleotides are required for its activity. Since only low levels of phosphoenolpyruvic carboxykinase activity are present in extracts prepared from both kinds of cells grown in a mineral glucose supplemented medium, and perhaps only trace amounts of the malic enzyme, phosphoenolpyruvic carboxytransphosphorylase, and of the enzyme requiring pyruvate, CO2, and adenosine triphosphate are present, it was concluded that PEP carboxylase is required for CO2 fixation in this organism. (Author)

Descriptors :   (*SALMONELLA, MUTATIONS), (*METABOLISM, SALMONELLA), CARBON DIOXIDE, ENZYMES, CARBOXY LYASES, OXIDATION, PYRUVATES, GLUCOSE, NUCLEOTIDES, ADENOSINE PHOSPHATES, ACETATES, GROWTH(PHYSIOLOGY)

Distribution Statement : APPROVED FOR PUBLIC RELEASE