PMID-sentid Pub_year Sent_text comp_official_name comp_offsetprotein_name organism prot_offset 17652174-2 2007 In both systems photochemistry begins by photo-oxidation of a chlorophyll a, but that in photosystem II (PS2) has a 0.7 eV higher midpoint potential than that in photosystem I (PS1), so their electronic structures must be very different. chlorophyll a 62-75 taste 2 receptor member 64 pseudogene Homo sapiens 105-108