EC Explorer

3.1.1.82

pheophorbidase

pheophorbide a + H₂O = pyropheophorbide a + methanol + CO₂ (overall reaction);; (1a) pheophorbide a + H₂O = C-13²-carboxypyropheophorbide a + methanol;;(1b) C-13²-carboxypyropheophorbide a = pyropheophorbide a + CO₂ (spontaneous)

phedase, PPD

pheophorbide-a hydrolase

This enzyme forms part of the chlorophyll degradation pathway, and is found in higher plants and in algae. In higher plants it participates in de-greening processes such as fruit ripening, leaf senescence, and flowering. The enzyme exists in two forms: type 1 is induced by senescence whereas type 2 is constitutively expressed [1,2]. The enzyme is highly specific for pheophorbide as substrate (with a preference for pheophorbide a over pheophorbide b) as other chlorophyll derivatives such as protochlorophyllide a, pheophytin a and c, chlorophyll a and b, and chlorophyllide a cannot act as substrates [2]. Another enzyme, called pheophorbide demethoxycarbonylase (PDC), produces pyropheophorbide a from pheophorbide a without forming an intermediate although the precise reaction is not yet known [1].

created 2007