Charles Gilvarg

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Although lysine (Lys) biosynthesis in plants is known to occur by way of a pathway that utilizes diaminopimelic acid (DAP) as a central intermediate, the available evidence suggests that none of the known DAP-pathway variants found in nature occur in plants. A new Lys biosynthesis pathway has been identified in Arabidopsis (Arabidopsis thaliana) that(More)
With the aim of elucidating how plants synthesize lysine, extracts prepared from corn, tobacco, Chlamydomonas and soybean were tested and found to lack detectable amounts of N-alpha-acyl-L,L-diaminopimelate deacylase or N-succinyl-alpha-amino-epsilon-ketopimelate-glutamate aminotransaminase, two key enzymes in the central part of the bacterial pathway for(More)
*Many methods for measuring creatine are known, the principal ones being direct calorimetric assay (l), indirect calorimetric assay (2), and destruction with bacterial adaptive enzymes (3). However, none of these methods are specific nor are they sensitive enough to detect very small amounts of creatine. rIhese assays have been used to examine urine and(More)
A variant of the diaminopimelate (DAP)-lysine biosynthesis pathway uses an LL-DAP aminotransferase (DapL, EC to catalyze the direct conversion of L-2,3,4,5-tetrahydrodipicolinate to LL-DAP. Comparative genomic analysis and experimental verification of DapL candidates revealed the existence of two diverged forms of DapL (DapL1 and DapL2). DapL(More)
Bacteroides fragilis and Clostridium thermocellum were recently found to synthesize diaminopimelate (DAP) by way of LL-DAP aminotransferase. Both species also contain an ortholog of meso-diaminopimelate dehydrogenase (Ddh), suggesting that they may have redundant pathways for DAP biosynthesis. The B. fragilis Ddh ortholog shows low homology with other(More)
Previous studies of the pathway of biosynthesis of diaminopimelic acid had indicated that pyruvic acid (1) and aspartic semialdehyde (2) were sources of the carbon skeleton of diaminopimelic acid. In addition, N-succinyl-cY-amino-e-ketopimelic acid had been established as an intermediary in the biosynthesis (3, 4). A comparison of the structures of these(More)
The pyruvate-aspartic semialdehyde condensing enzyme, which occurs at the branch point in the aspartic acid family of amino acids leading to diaminopimelic acid and lysine biosynthesis, has been purified 5000-fold from crude extracts of Escherichia coli W. The protein has been shown to be homogeneous by polyacrylamide gel electrophoresis and bears a net(More)
In order to facilitate the elucidation of the remaining undetermined steps in diaminopimelic acid and lysine biosynthesis, mutants blocked in the pathway between aspartic semialdehyde and a-N-succinyl-e-ket.opimelic acid were sought. A mutant (M-203) with a requirement for diaminopimelate and lysine was obtained. An examination of the enzymatic composition(More)
The extent and rate of cross-linking of diaminopimelic acid in the peptidoglycan of Bacillus megaterium have been determined by a new procedure. The method is based on the reaction of nitrous acid with the unprotected amino groups of non-cross-linked diaminopimelic acid. Pulse label experiments in a mutant where diaminopimelic acid is incorporated(More)