Pheophytin a is a derivative formed when chlorophyll a loses its central Mg²⁺ ion under acidic conditions or through enzymatic action. It retains the porphyrin ring structure and possesses certain light-absorbing properties. It is commonly used to study electron transfer processes in photosynthesis, particularly as a model molecule for electron acceptors and reaction intermediates in photosystem II. As a photosensitizer, demagnesium chlorophyll a can generate reactive oxygen species through photodynamic therapy upon activation by red light at 660 nm, inducing apoptosis and necrosis in cancer cells.

脱镁叶绿素 A