This project has 4 specific objectives. 1. To complete a study on the stereochemistry of the 6-B- OH-intermediate of chlorophyll. 2. To study the enzymatic formation of protochlorophyllide by a mixed function oxygenase using 18O2 incubators. 3. To conduct metabolic studies with 6-B-ketopropionate methyl ester, 7-propionic acid to assay for protochlorophyllide formation catalyzed by soluble chloroplast proteins and fragments of chloroplast membranes. 4. To determine the number of enzymes required for the cyclization using monoesters. The developing chloroplasts will be fractionated to study these metabolic transformations with organelle-free (and possibly soluble) extracts.%%% This research investigates the biosynthesis of a universal feature of all plant and bacterial chlorophylls; the formation of one of the rings. Chlorophylls are the essential catalysts in photosynthesis.***//