Oxygen-dependent H2O2 production by Rubisco.
Oxygen and ribulose-1,5-bisphosphate dependent, H(2)O(2) production was observed with several wild type Rubisco enzymes using a sensitive assay. H(2)O(2) and d-glycero-2,3-pentodiulose-1,5-bisphosphate, a known and potent inhibitor of Rubisco activity, are predicted products arising from elimination of H(2)O(2) from a peroxyketone intermediate, specific to oxygenase activity. Parallel assays using varying CO(2) and O(2) concentrations revealed that the partitioning to H(2)O(2) during O(2) consumption by spinach Rubisco was constant at 1/260-1/270. High temperature (38 degrees C), which reduces Rubisco specificity for CO(2) versus O(2), increased the rates of H(2)O(2) production and O(2) consumption, resulting in a small increase in partitioning to H(2)O(2) (1/210). Two Rubiscos with lower specificity than spinach exhibited greater partitioning to H(2)O(2) during catalysis: Chlamydomonas reinhardtii (1/200); and Rhodospirillum rubrum (1/150).
United States Department of Agriculture, Agricultural Research Service, Photosynthesis Research Unit, USA.
Kangmin
K
Kim
Archie R
AR
Portis
D006861:Hydrogen Peroxide / Q000378:metabolism*; D007700:Kinetics; D010100:Oxygen / Q000378:metabolism*; D010105:Oxygenases / Q000378:metabolism; D012273:Ribulose-Bisphosphate Carboxylase / Q000378:metabolism*; D018724:Spinacia oleracea / Q000201:enzymology
D006861:Hydrogen Peroxide; D010105:Oxygenases; D012273:Ribulose-Bisphosphate Carboxylase; D010100:Oxygen