   1.4.5.1 | 3,4-dehydro-DL-proline + oxidized 2,6-dichloroindophenol |
when membrane fractions from Escherichia coli strain UMM5 (putA1::Tn5 proC24) lacking both L-proline dehydrogenase and L-DELTA1-pyrroline-5-carboxylate reductase are incubated with 3,4-dehydro-DL-proline, pyrrole-2-carboxylate is formed. Oxidation of 3,4-dehydro-DL-proline by membrane fractions from strain UMM5 is induced by growth in minimal medium containing D- or L-alanine. An Escherichia coli strain with no D-alanine dehydrogenase activity due to the dadA237 mutation is unable to oxidize either 3,4-dehydro-D-proline or D-alanine, as are spontaneous Dad- mutants of Escherichia coli strain UMM5. Membrane fractions containing D-alanine dehydrogenase also catalyze the oxidation of D-2-aminobutyrate, D-norvaline, D-norleucine, cis-4-hydroxy-D-proline, and DL-ethionine. D-Alanine dehydrogenase is responsible for the residual 3,4-dehydro-DL-proline oxidation activity in putA proC mutants of Escherichia coli. This enzyme plays a general role in the metabolism of D-amino acids and their analogues |
