Co-translational modification

The incorporation of 3H from [3H]arabinose into Fer-Ara2 units showed a lag of about 4.2 min, after which it too became linear. This means that as little as 0.7 min after their incorporation into a (possibly still nascent) polysaccharide, [3H]arabinose residues were susceptible to feruloy-lation. The feruloylation reaction is thus likely to have been occurring in the endomembrane system, co-synthetically, as one of the highly regulated parts of the sophisticated polysaccharide-biosynthetic machinery. This can be compared to the co-translational modification known to occur in many proteins. 

Dolichols (98), a family of polyisoprenoid alcohols, have isolated from all eukaryotic cells or archaebacteria." They play a role in the co-translational modification of proteins and are known in iV-glycosylation in the form of dolichol phosphate. The synthesis of the photochemical probes 118 and 119 bearing a photoreactive group [3-(trifiuoromethyl)-3-aryldiazirine], analogues of dolichol and dolichol phosphate, is described in Scheme 5.19. The synthetic strategy involves the sequential alkylation of a monoterpenoid hydroxysulfonyl dianion with allyl chlorides, and MBH adduct 102 as a starting material. 

Co - translational modification Post- translational modification Processing... 

Graves DJ, Martin BL, WangJH Co-and Post-translational Modification ofiProteins Chemical Principles and Biological Effects. Oxford Univ Press, 1994. 

These results are particularly relevant, since such constant interdistances may be related to the chemical properties of the proteins present in the sample. For example, they may be consistent with protein isoforms differing in a constant variation of the number of ionogenic groups in the molecule suggesting the presence of co- and post-translational modifications (Wilkins et al., 1997 Righetti et al., 2001 Mann and Jensen, 2003 Farriol-Mathis et al., 2004 Hamdan and Righetti, 2005). 

Catalysts of Collagen Folding, Co- and Post-Translational Modification... 

D. J. Graves, B. L. Martin J. H. Wang (1994) Co- and Post-Translational Modification of Proteins Chemical Principles and Biological Effects, pp. 348ff, Oxford University Press, Oxford. 

Most IFNs have now been produced in a variety of expression systems including E. coli, fungi, yeast and also some mammalian cell lines such as Chinese hamster ovary (CHO) cell lines and monkey kidney cell lines. Most IFNs currently in medical use are recombinant human (rh) products produced in E. coli. The inability of E. coli to carry out post-translational modifications is in most instances irrelevant, as the majority of human IFN-as, as well as IFN-jS, are not normally glycosylated. While IFN-y is glycosylated, the E. co/i-derived unglycosylated form displays a biological activity identical to the native human protein. 

Graves, D. J., Martin, B. L., and Wang, J. H. (1994) Co-and post-translational modification of proteins, Oxford Univ. Press, New York... 

Gooley, A. A. and Paker, N. H. (1997) The importance of protein co- and post-translational modifications in proteome projects, in Proteome research new frontiers in functional genomics, Wilkins M. R., Williams K. L., Appel R. D., and Hochstrasser D. F. (eds), Springer-Verlag Berlin Heidelberg. 

In eukaryotic organisms, transcription regulation is a complex process that demands coordinated interaction of several genetic elements. The efficiency of this process mainly depends on the promoter/enhancer sequences, the copy number of the gene, and the structure and elements present at the insertion site in the host s chromatin. On the other hand, the co-transcriptional modifications (capping, splicing, polyadenylation, and transport to cytoplasm) on the primary transcript determine the stability, turnover rate, and translational capacity of the future mRNA. 

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