The binding of thiamine pyrophosphate (TPP) to several enzymes has been determined by measuring cofactordependent activity after passage of each enzyme through a column of Sephadex G-25 to remove non-protein-bound cofactors. TPP was found to be bound irreversibly to yeast and Zymomonas pyruvate decarboxylases, Aerobacter (Yacetolactate synthetase, and Escherichia glyoxylate carboligase. Cofacto...

The crystal structure of the E1 component from the Escherichia coli pyruvate dehydrogenase multienzyme complex (PDHc) has been determined with phosphonolactylthiamin diphosphate (PLThDP) in its active site. PLThDP serves as a structural and electrostatic analogue of the natural intermediate alpha-lactylthiamin diphosphate (LThDP), in which the carboxylate from the natural substrate pyruvate is ...

Xylose is rarely described as a component of bacterial glycans. UDP-xylose is the nucleotide-activated form necessary for incorporation of xylose into glycans and is synthesized by the decarboxylation of UDP-glucuronic acid (UDP-GlcA). Enzymes with UDP-GlcA decarboxylase activity include those that lead to the formation of UDP-xylose as the end product (Uxs type) and those synthesizing UDP-xylo...

The three-dimensional structure of the pyridoxal 5'-phosphate (PLP)-dependent L-threonine-O-3-phosphate decarboxylase (CobD) from Salmonella enterica is described here. This enzyme is responsible for synthesizing (R)-1-amino-2-propanol phosphate which is the precursor for the linkage between the nucleotide loop and the corrin ring in cobalamin. The molecule is a molecular dimer where each subun...

The most commonly occurring of the natural polyamines are putrescine [ Nl ll(CI ll),N14?, a diaminel, spermidine [ Nl 12(C€12)3Nl l(C142),NIIl. a triamine] and spermine [ Nl il(Cl 12);NI l(C€Il),N€I(CI 1?)?NI ?. a tetramine]. One or more of these compounds are present in every living cell. All are found in eukaryotes; spermine is absent from most prokaryotes. The polyamines are essential for ce...

Procedures have been reported for the use of specific bacterial decarboxylases to assay individual amino acids by measurement of the CO2 evolved (1). Since 1 mole of amine is formed for each mole of amino acid decarboxylated, it should also be possible to estimate the amount of amino acid from the quantity of amine formed. When L-phenylalanine is decarboxylated by L-phenylalanine decarboxylase,...

Most physiology comparisons of C3 and C4 plants are made under current or elevated concentrations of atmospheric CO2 which do not reflect the low CO2 environment under which C4 photosynthesis has evolved. Accordingly, photosynthetic nitrogen (PNUE) and water (PWUE) use efficiency, and the activity of the photosynthetic carboxylases [Rubisco and phosphoenolpyruvate carboxylase (PEPC)] and decarb...