It is proposed to extend our in vitro studies of: (1) the biosynthesis of homarine from glycine and (2) the biosynthesis of quinolinic acid and N-methyl quinolinate from acetate. Co-factor requirements, and effects of temperature, pH and ionic strength will be investigated. Carboxyl 14C-homarine will be synthesized and utilized to study the metabolic fate of homarine in vitro and in vivo. Since we have demonstrated a methyl-transfer function for homarine, a similar investigation of N-methyl quinolinate and other N-methyl pyridinium compounds will be carried out.