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R r r i f i M t i o n of g t y Y o s m sCrude glycosomes (i.e. the 48 000 1 p e l l e t from a homogenate) were prepared according t o the d i f f e r e n t i a l centrifugation procedure described i n Scheme I from [lo]. The pelleted glycoscues were resuspepded i n 25 nU TrisfHCI pH 7.8. containing

Glycosomes, the microbodies of Trypanosoma brucei, contain a number of enzymes involved in glucose and glycerol metabolism. The biogenesis of three of these enzymes has been studied. Aldolase, D-glyceraldehyde-3-phosphate dehydrogenase and NAD-linked glycerol-3-phosphate dehydrogenase are all synthesized in the cytosol on free rather than on membrane-bound polysomes. In vitro, as well as in vivo, these polypeptides are synthesized at their mature size, and no evidence was found for any processing upon entry into the glycosomes. Continuous and pulse-chase labelling experiments with procyclic trypomastigotes revealed that the enzymes have a half-life in the cytosol of -3 min or less, and then turn over rapidly in the glycosomes, with half-lives as short as 30 min.

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