4.1.2.48 glycine + glycolaldehyde low-specificity L-threonine aldolase is involved in a serendipitous pathway that converts 3-phosphohydroxypyruvate, an intermediate in the serine biosynthesis pathway, to L-4-phosphohydroxythreonine, an intermediate in the pyridoxal-5'-phosphate synthesis pathway in a strain of Escherichia coli that lacks 4-phosphoerythronate dehydrogenase 4.1.2.48 L-Thr - 4.1.2.48 additional information glycine metabolism