GABA TRANSMINASE PROVIDES AN ALTERNATIVE ROUTE OF BETA-ALANINE SYNTHESIS IN ASPERGILLUS-NIDULANS

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 β-alanine, respectively. A pantoC- mutant is tentatively considered to be bloaked in conversion of 5,6-dihydrouracil to β-ureidopropionate. An alternative route of β-alanine biosynthesis occurs by the transamination of malonic semialdehyde, catalysed by GABA transaminase. The possibility that β-alanine can be replaced by certain structurally related compounds and yet nevertheless yield biologically active coenzyme A analogues is discussed. © 1978 Springer-Verlag.