title: GABA transaminase provides an alternative route of beta-alanine synthesis in Aspergillus nidulans.
abstract: Three unlinked genes where mutation can lead to D(+)-pantothenic acid auxotrophy in Aspergillus nidulans have been identified. pantoA is probably the structural gene for pantothenate synthetase (EC 6.3.2.1) whilst pantoB and pantoC are involved in the syntheses of D-pantoic acid and beta-alanine, respectively. A pantoC- mutant is tentatively considered to be blocked in conversion of 5,6-dihydrouracil to beta-ureidopropionate. An alternative route of beta-alanine biosynthesis occurs by the transamination of malonic semialdehyde, catalysed by GABA transaminase. The possibility that beta-alanine can be replaced by certain structurally related compounds and yet nevertheless yield biologically active coenzyme A analogues is discussed.
mesh_terms: D000612:4-Aminobutyrate Transaminase / Q000378:metabolism*; D000409:Alanine / Q000096:biosynthesis*; D001233:Aspergillus nidulans / Q000201:enzymology / Q000235:genetics*; D005796:Genes; D009154:Mutation; D010205:Pantothenic Acid / Q000235:genetics; D000637:Transaminases / Q000378:metabolism*; D005680:gamma-Aminobutyric Acid
chemical_list: D010205:Pantothenic Acid; D005680:gamma-Aminobutyric Acid; D000637:Transaminases; D000612:4-Aminobutyrate Transaminase; D000409:Alanine