Search results
Results from the WOW.Com Content Network
Ribulose is a ketopentose — a monosaccharide containing five carbon atoms, and including a ketone functional group. It has chemical formula C 5 H 10 O 5 . Two enantiomers are possible, d -ribulose ( d -erythro-pentulose) and l -ribulose ( l -erythro-pentulose).
Ribulose 1,5-bisphosphate (RuBP) is an organic substance that is involved in photosynthesis, notably as the principal CO 2 acceptor in plants. [ 1 ] : 2 It is a colourless anion, a double phosphate ester of the ketopentose ( ketone -containing sugar with five carbon atoms) called ribulose .
During the oxidative phase of the pentose phosphate pathway, it is formed from 6-phosphogluconolactone by 6-phosphogluconolactonase, and in turn, it is converted to ribulose 5-phosphate by phosphogluconate dehydrogenase, in an oxidative decarboxylation which also produces NADPH.
RuBisCO is important biologically because it catalyzes the primary chemical reaction by which inorganic carbon enters the biosphere.While many autotrophic bacteria and archaea fix carbon via the reductive acetyl CoA pathway, the 3-hydroxypropionate cycle, or the reverse Krebs cycle, these pathways are relatively small contributors to global carbon fixation compared to that catalyzed by RuBisCO.
Ribose-5-phosphate isomerase (Rpi) encoded by the RPIA gene is an enzyme (EC 5.3.1.6) that catalyzes the conversion between ribose-5-phosphate (R5P) and ribulose-5-phosphate (Ru5P). It is a member of a larger class of isomerases which catalyze the interconversion of chemical isomers (in this case structural isomers of pentose).
Depending on the body's state, ribulose 5-phosphate can reversibly isomerize to ribose 5-phosphate. Ribulose 5-phosphate can alternatively undergo a series of isomerizations as well as transaldolations and transketolations that result in the production of other pentose phosphates as well as fructose 6-phosphate and glyceraldehyde 3-phosphate ...
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
It is a ketose sugar formed from ribulose-5-phosphate by ribulose-5-phosphate epimerase. In the non-oxidative branch of the pentose phosphate pathway, xylulose-5-phosphate acts as a donor of two-carbon ketone groups in transketolase reactions.