Alanine, biosynthesis catabolism

In contrast to the catabolic nature of /7-alanine and /7-aminobutyric acid biosynthesis, the generation of higher /7-amino acids usually starts from the corresponding a-amino acid. The shift of the amino group is catalyzed by different types of aminomutase. 

The biosynthetic source of the pyridone ring of 87 was investigated [260]. Thymine was found to inhibit uracil catabolism and 87 biosynthesis by Nocardia lactamdurans this inhibition was reversed by uracil catabolites. Both [5,6-3H]-uracil and [4,5-13c]-uracil were incorporated, with both labelled carbons of the latter being incorporated as a unit at C(4) and C(5) of 87. The proposed biosynthetic pathway (Scheme 2) involved catabolism of uracil to p-alanine, which was then incorporated into the pyridone ring of 87 [260]. 

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