Biosynthesis in vitro of homarine and pyridine carboxylic acids in marine shrimp.

Minces and homogenates of muscle obtained from the marine shrimp Penaeus duorarum are capable of synthesizing homarine from [14C]glycine. Glycine carbon atoms are incorporated into homarine but not significantly into picolinate or quinolinate. [2-14C]Acetate is readily incorporated into quinolinate in the in vitro system but only slightly into homarine and not at all into picolinate. Quinolinic acid is rapidly methylated to N-methyl quinolinate which is not decarboxylated to form homarine. Procedures have been developed for the satisfactory separation of N-methyl quinolinate from homarine.