Sedoheptulose-bisphosphatase

Glyceraldehyde 3-phosphate dehydrogenase Calvin cycle, gluconeogenesis, glycolysis Sedoheptulose bisphosphatase Calvin cycle... 

Abbreviations FBPase, fructosebisphosphatase SBPase, sedoheptulose bisphosphatase Ru, ribulose Fru, fructose Sed, sedoheptulose ... 

Increased sedoheptulose bisphosphatase greater Calvin cycle activity. (Tamoi et al., 2006) Arabidopsis thaliana Inserted -30% SBPase gene from Chlamydo -monas reinhardtii -50% Leaf RuBP also increased -25%... 

Role of Sedoheptulose 1,7-I5isphosphata.se What effect on the cell and the organism might result from a defect in sedoheptulose 1,7-bisphosphatase in (a) a human hepato-cyte and (b) the leaf cell of a green plant ... 

Fructose-1,6-bisphosphatase Sedoheptulose-1,7-bisphosphatase Glyceraldehyde-3-phosphate dehydrogenase NADP-malate dehydrogenase Phosphoribulokinase Thylakoid ATP-synthase... 

Answer Ribulose 5-phosphate kinase, fructose 1,6-bisphosphatase, sedoheptulose 1,7-bisphosphatase, and glyceraldehyde 3-phosphate dehydrogenase would be inhibited. All have mechanisms requiring activation by reduction of a critical disulfide bond to a pair of —SH groups. Iodoacetate reacts irreversibly with free —SH groups. 

A clear demonstration that aldolase is a mandatory catalyst in liver PPP involved the immunochemical evidence of Bleakely et al. (43) who showed the total cessation of hexose 6-P formation when liver aldolase antibody titrated the removal of aldolase from the system where Rib 5-P was reacted with the same rat liver enzyme preparation that established the Fig. 2 scheme. Irrespective of the other contrary data, this evidence alone showed another reaction mechanism involved Aid in liver PPP. The claim that aldolase is an essential enzyme in the PPP was also supported by data of (60) in which, using an in vitro construction of a PPP preparation for the complete oxidation of Glc, noted the formation of Oct-P and the need to include aldolase and sedoheptulose 1,7-bisphosphatase for the construction system to work. 

It is also an intermediate in the Calvin cycle, resulting from the action of sedoheptulose-1,7-bisphosphatase on sedoheptulose-1,7-bisphosphate. 

Sedoheptulose-1,7-bisphosphatase is an enzyme of the Calvin cycle that catalyzes the following reaction ... 

We have isolated and sequenced cDNAs for wheat phosphoribulokinase (PRK), for chloroplast fructose-1, 6-bisphosphatase (FBP) and for both the chloroplast and cj osolic versions of phosphoglycerate kinase (PGK). We are at present sequencing a putative cDNA clone for sedoheptulose-l,7-bisphosphatase (SBP) and isolating the coding sequence of cytosolic FBP. For the sake of comparison, we have also sequenced the E coU gene for FBP (3). 

Chloroplast and cytosolic Fructose-1,6-bisphosphatase (FbPase) and Sedoheptulose-l,7-bisphosphatase (SBPase) have been investigated mainly from spinach leaves (1,2,3). We present data which show significant differences for these enzymes from pea leaves. 

CONTROL OF STROMAL FRUCTOSE 1.6 BISPHOSPHATASE AND SEDOHEPTULOSE 1.7 BISPHOSPHATASE BY METABOLITE LEVELS... 

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