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Results for “PIMELIC ACID”

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At least 163 records · Page 9Linked to original sources
PubMed1995

Pre-column fluorescence derivatization using leucine-coumarnylamide for HPLC determination of mono- and dicarboxylic acids in plasma.

A sensitive HPLC assay utilising a simple fluorescence pre-column labelling technique was developed for plasma level monitoring of different types of mono- and dicarboxylic acids. Carboxylic acids form mixed anhydrides with ethyl chloroformate in the presence of triethylamine; the mixed anhydrides further react with L-leucine-4-methyl-7-coumarinylamide, forming highly fluorescent and stable amides. Drugs with no chromophore (azelaic acid, and its longer carbon chain analogues) or week UV absorption (artelinic acid, enalaprilat) were used as model compounds. The plasma samples were extracted using ion exchange solid phase cartridges. The separation was performed on an Axxiom C18 (5 microns, 4.6 x 250 mm) column. The detector wavelengths were set at 330 nm for excitation and 390 nm for emission.

Animals↗
PubMed1965

PURIFICATION AND PROPERTIES OF DIAMINOPIMELATE DECARBOXYLASE FROM ESCHERICHIA COLI.

1. Diaminopimelate decarboxylase from a soluble extract of Escherichia coli A.T.C.C. 9637 was purified 200-fold by precipitation of nucleic acids, fractionation with acetone and then with ammonium sulphate, adsorption on calcium phosphate gel and chromatography on DEAE-cellulose or DEAE-Sephadex. 2. The purified enzyme showed only one component in the ultracentrifuge, with a sedimentation coefficient of 5.4s. One major peak and three much smaller peaks were observed on electrophoresis of the enzyme at pH8.9. 3. The mol.wt. of the enzyme was approx. 200000. The catalytic constant was 2000mol. of meso-diaminopimelic acid decomposed/min./mol. of enzyme, at 37 degrees . The relative rates of decarboxylation at 25 degrees , 37 degrees and 45 degrees were 0.17:1.0:1.6. At 37 degrees the Michaelis constant was 1.7mm and the optimum pH was 6.7-6.8. 4. There was an excess of acidic amino acids over basic amino acids in the enzyme, which was bound only on basic cellulose derivatives at pH6.8. 5. The enzyme had an absolute requirement for pyridoxal phosphate as a cofactor; no other derivative of pyridoxine had activity. A thiol compound (of which 2,3-dimercaptopropan-1-ol was the most effective) was also needed as an activator. 6. In the presence of 2,3-dimercaptopropan-1-ol (1mm), heavy-metal ions (Cu(2+), Hg(2+)) did not inhibit the enzyme, but there was inhibition by several amino acids with analogous structures to diaminopimelate, generally at high concentrations relative to the substrate. Penicillamine was inhibitory at relatively low concentrations; its action was prevented by pyridoxal phosphate.

Amino Acids↗
PubMed1964

THE BIOTIN ENZYMES.

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Adenine Nucleotides↗
PubMed1963

DIAMINOPIMELIC ACID DECARBOXYLASE OF THE AGENT OF MENINGOPNEUMONITIS.

Moulder, James W. (University of Chicago, Chicago, Ill.), Dorothy L. Novosel, and Ilse C. Tribby. Diaminopimelic acid decarboxylase of the agent of meningopneumonitis. J. Bacteriol. 85:701-706. 1963.-Evidence is presented for the presence in meningopneumonitis particles and extracts of an enzyme decarboxylating alpha, epsilon-diaminopimelic acid to lysine and for the absence of a corresponding enzyme in the uninfected host. Properties of the enzyme are described and compared with those of bacterial diaminopimelic acid decarboxylases. The significance of these observations with respect to the mode of lysine biosynthesis in the psittacosis group and to its phylogenetic origin is pointed out.

Carboxy-Lyases↗
PubMed1964

DEPENDENCE OF THE CONTENT OF CELL ENVELOPES ON THE GROWTH RATE OF BACILLUS MEGATERIUM.

Sud, I. J. (Tufts University School of Medicine, Boston, Mass.), and M. Schaechter. Dependence of the content of cell envelopes on the growth rate of Bacillus megaterium. J. Bacteriol. 88:1612-1617. 1964.-The amount of cell-wall and cell-membrane material was measured in Bacillus megaterium growing at different steady-state rates. On a dry weight basis, the content of wall hexosamine and diaminopimelic acid, and of membrane lipid phosphorus was found to be inversely proportional to the rate of growth. During the transition from slow to fast growth, the synthesis of envelope materials showed a lag of 20 to 30 min. Possible implications of these findings are discussed in terms of regulatory mechanism.

Bacillus megaterium↗
PubMed1973

Identification of prenol intermediates of wall biosynthesis in growing cells of Lactobacillus plantarum.

The incorporation of (14)C-mevalonic acid by Lactobacillus plantarum predominantly into C(55) prenol made it possible to determine the distribution of (14)C-prenol between all its derivatives. In logarithmic-phase cells, 25% of the prenol was free, 31% was as monophosphate, 4% as pyrophosphate, 12% as peptidoglycan precursor, and 28% as glyco-phospho-prenol. The glyco-phospho-prenol contained rhamnose, and probably glucose, galactose, and ribitol phosphate, and it may, therefore, be involved in polysaccharide and teichoic acid biosynthesis. The proportion of free prenol increased, up to 73%, as the cell culture aged. Free prenol was also formed when cells were incubated in buffer. The free prenol was readily reutilized when cells were returned to growth medium.

Carbohydrates↗
PubMed1979

Peptidoglycan turnover during growth of a Bacillus megaterium Dap- Lys- mutant.

The aim of this study was to ascertain whether or not the absence of cell wall growth zones, deduced from the analysis of autoradiographs of DL-[3H]mesodiaminopimelic acid pulse-labeled cells of a Dap- Lys- mutant of Bacillus megaterium, was due to a high peptidoglycan turnover. Turnover was determined in very precise experimental conditions because two kinds of turnover occurred: a low, acid-soluble turnover and a high, acid-insoluble one. The latter was detected during a chase in the culture medium when bacteria were centrifuged before treatment with trichloroacetic acid. Otherwise the acid-insoluble released material precipitated with the bacteria. In the electron microscope this material presented a globular structure and contained both peptidoglycan and teichoic acid. The acid-insoluble turnover was mainly produced by a lytic acitivity that was released into the culture medium. This thermolabile activity was not due to cell lysis. It was implicated in septum cleavage and in the detachment of wall fragments from the cell surface, but did not seem indispensable for cell elongation. The acid-soluble turnover was much weaker and seemed to be indispensable for cell elongation.

Bacillus megaterium↗