A -Pyrroline-5-carboxylate dehydrogenase

FIG. 5.1 Proline metabolism. 1, Proline oxidase 2, A -pyrroline-5-carboxylate reductase 3, spontaneous reaction 4, A -pyrroline-5-carboxylate dehydrogenase 5, glutamate dehydrogenase 6, see Fig. 5.2. 

The final step in the conversion of proline to glutamate is the oxidation of pyrroline-5-carboxylate to glutamate. Since pyrroline-5-carboxylate is in equilibrium in solution with its straight chain form, glutamate-y-semialdehyde it is possible that the latter compound is the substrate for this last step. An enzyme A -pyrroline-5-carboxylate dehydrogenase (E.C. 1.5.1.12) has been found in mitochondrial preparations fixim several higher plant seedlings (Stewart and Lai, 1974) which will catalyze this reaction. 

---