Enzymes of arginine biosynthesis in methanogenic ..
Genes and enzymes of the acetyl cycle of arginine biosynthesis in Corynebacterium glutamicum: enzyme ..
Enzymes of arginine biosynthesis ..
Methanobacterium thermoautotrophicum, Methanococcus vannielii andMethanobrevibacter arboriphilus, the 3 methanogenic bacteria tested, possessed an ornithine acetyltransferase and an arginine-sensitiveN-acetylglutamate 5-phopshtransferase. These 2 enzymes, as well as acetylornithinase and ornithine carbamoyltransferase, were insensitive to oxygen and were present at activity levels comparable to the levels observed in eubacteria.
Seven “fundamental” amino acids have relatively simple biosynthetic pathways. Others require longer pathways involving numerous enzymes. One amino acid produced by a complex pathway is arginine (). Bacterial arginine biosynthesis generally involves about a dozen different enzymes distributed among four to eight operons. Operon expression is regulated by an arginine repressor that binds the promoter of each operon to prevent transcription in the presence of sufficient arginine for cell needs. In some species, the arginine repressor also activates enzymes of arginine catabolism, making the excess amino acid available as a carbon source.
Evolution of Arginine Biosynthesis in the Bacterial …
Not surprisingly, the presence of tryptophan in the cell represses expression of its own biosynthetic enzymes. Repression of the operon includes two mechanisms: the Trp repressor, effective over moderate to high levels of tryptophan; and an RNA loop mechanism called attenuation, sensitive to lower levels of tryptophan (discussed in ). Attenuation involves the destabilization of the transcription complex by formation of a specific stem loop on the nascent mRNA. The mechanism of attenuation in was discovered in 1981 by Charles Yanofsky, winner of a National Medal of Science in 2003. Several other amino acids commonly show attenuation in bacteria—particularly histidine, threonine, phenylalanine, valine, and leucine.
Enzymes of Arginine-Biosynthesis in Methanogenic Bacteria
Pathways of arginine biosynthesis in extreme thermophilic archaeo ..
arginine biosynthesis in extreme thermophilic ..
09/11/2006 · ..
Genes and Enzymes of the Acetyl Cycle of Arginine Bio Synthesis in C
ASMscience | Biosynthesis of Arginine and Polyamines
The review summarizes what is known about the enzymes involved in the arginine pathway of ..
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