Mechanism of glyceraldehyde‐3‐phosphate transfer from aldolase to glyceraldehyde‐3‐phosphate dehydrogenase

• The catalytic interaction of glyceraldehyde‐3‐phosphate dehydrogenase with glyceraldehydes‐3‐phosphate has been examined by transient‐state kinetic methods. The results confirm previous reports that the apparent Km for oxidative phosphorylation of glyceraldehydes‐3‐phosphate decreases at least 50‐fold when the substrate is generated in a coupled reaction system through the action of aldolase on fructose 1,6‐bisphosphate, but lend no support to the proposal that glyceraldehydes 3‐phosphate is directly transferred between the two enzymes without prior release to the reaction medium. A theoretical analysis is presented which shows that the kinetic behaviour of the coupled two‐enzyme system is compatible in all respects tested with a free‐diffusion mechanism for the transfer of glyceraldehydes 3‐phosphate from the producing enzyme to the consuming one.

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NATURVETENSKAP  -- Biologi -- Biokemi och molekylärbiologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Biochemistry and Molecular Biology (hsv//eng)

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