[Study, by an enzymatic method, of the isomers of L-proline (3H-4) and of the effects of preservation].

By use of procollagen proline hydroxylas which catalyses the substitution of the hydrogen in the trans position on carbon 4 with an hydroxyl on L-proline residues of procollagen, we have shown that the L-[3H-4] proline product of C.E.N. Saclay contained 29 per cent of the trans and 71 per cent of the cis form. It was also possible to verify the molecular stability of the isomers and that a small amount of tritium was randomly linked to the whole molecule.