#photorespiration #plants #mscbotany #photosynthesis #plantphysiology
Photorespiration or C2 cycle (Dicker and Tio, 1959) refers to a process in plant metabolism where the enzyme RuBisCO oxygenates RuBP, wasting some of the energy produced by photosynthesis.
It is a metabolic repair system, enables the CO2 fixation enzyme RuBisco to sustainably operate in the presence of oxygen.
Rubisco is a bifunctional enzyme that catalyzes not only RuBP carboxylation but also RuBP oxygenation
RuBP oxygenation generates only one molecule of PGA and one molecule of 2-phosphoglycolate.
2-phosphoglycolate is a toxic compound to many enzymes in photosynthetic metabolism.
Photorespiratory pathway also rescues ¾ of the carbon in phosphoglycolate that would be otherwise inaccessible for further metabolism...