Genetic and biochemical studies of genes controlling the synthesis of threonine and methionine in Saccharomyces.

ranched pathway for the biosynthesis of threonine and methionine in T:fai, as described by BLACK and WRIGHT (1955 a,b,c), includes three steps leading to the common precursor homoserine: I. Aspartokinase ATP : L-aspartate 4phosphotransferase-2.7.2.4: ATP + L-aspartate e ADP + 4 phospho-L-aspartate (Asp-PO,) 11. Aspartate semialdehyde (ASA) dehydrogenase L-aspartate p-semialdehyde : NADP oxidoreductase (phosphorylating) 1.2.1.1 1 : L-aspartate p-semialdehyde (ASA) + phosphate + NADP e L-P-aspartylphosphate (AspPO,) + NADP,