The stereospecific interaction between chlorophylls and chlorophyllase. Possible implication for chlorophyll biosynthesis and degradation.

Chlorophyllase-catalyzed hydrolysis and esterification of chlorophylls, bacteriochlorophylls, and their free acids, respectively, depend on the configuration around the C-13(2) atom of the corresponding substrate. The data suggest that the enzyme interacts preferentially with compounds having the isocyclic carbomethoxy and the C-17 propionic residues facing opposite sides of the porphyrin macrocycle. The relevance of this observation to chlorophyll biosynthesis and degradation in vivo is briefly discussed.