Anatomy and Cell Biology 4429A Lecture Notes - Lecture 10: Glycosylation, Plasmalogen, Fibroblast
12 Jan 2018
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Structure and function of peroxisomes (microbodies: single-membrane bound organelle, lack of dna or ribosomes, typically ovoid, 0. 1-1 microns in diameter, contain enzymes (>50) of, -oxidation, nitrogenous waste processing, plasmalogen synthesis. Lipid membrane that makes up neurons: sterol metabolism, methanol assimilation, glyoxalate cycle, oxidases use o2 to oxidize various substances forming h2o2: Rh2 + o2 -r + h2o2: catalase decomposes h2o2 into h2o and o2: Primary role of peroxisomes has been assumed to be the sequestration of the h2o2 producing and consuming reactions of the cell. Peroxisomal proteins: synthesized from nuclear-encoded genes, on free ribosomes in the cytosol. Imported post-translationally, with a half-life in the cytosol of approximately 20 minutes: specific peroxisomal-targeting sequences (pts), at the carboxy terminus, no glycosylation, translocated as folded proteins. Import does not involve proteolytic cleavage (cannot tell whether the protein was fully imported or partially imported using sds: proteins involved in biogenesis or import called peroxins (pex1, pex2, etc. )
