It catalyzes the reaction Chlorophyllase can be found in the chloroplast, thylakoid membrane and etioplast of at least higher plants such as ferns, mosses, brown and red algae and diatoms.

[1][2][3] Of high importance to all photosynthetic organisms is chlorophyll, and so, its synthesis and breakdown are closely regulated throughout the entire life cycle of the plant.

Chlorophyllase's role is two-fold as it functions in both de-greening processes, such as autumnal coloration, and is also thought to be involved in turnover and homeostasis of chlorophylls.

Chlorophyllase catalysis of the initial step of chlorophyll breakdown is important for plant development and survival.

Next, through the reverse reaction, the oxygen on the hydroxy group from the water in the previous step attacks the carbonyl of the intermediate in order to form another tetrahedral transition state.

The double bond of the carbonyl forms again and the serine residue returns to chlorophyllase and the ester of the chlorophyll is now a carboxylic acid.

Recent data, however, suggests that chlorophyllase is expressed at low levels during natural fruit development, when chlorophyll catabolism usually takes place.

Recent studies inspired by inconsistent data revealed that chlorophyllase in Citrus lacking the 21 amino sequence on the N-terminal results in extensive chlorophyll breakdown and the degreening effect that should occur in vivo.

This data suggests that the mature protein comes in contact with its substrate more readily because of the N-terminal sequence and some natural regulation occurs that directly affects enzyme activity.

[9] Chlorophyllide, the product of the reaction catalyzed by chlorophyllase, spontaneously combines with plant lipids such as phosphatidylcholine liposomes along with sulfoquinovosyl diacylglycerol.

Histidne and aspartic acid residues are also a part of the catalytic triad of chlorophyllase as a serine hydrolase.