Postsynthetic modification covalent

Biotin is bound covalently to enzymes by a peptide fink to the s -amino group of a lysine residue, forrningbiotinyl-s-arnino-lysine orbiocytin (see Figure 11.1). This postsynthetic modification is catalyzed by holocarboxylase synthetase with the intermediate formation of biotinyl-5 -AMP. In bacteria, this intermediate also acts as a potent repressor of all four enzymes of biotin synthesis. 

Poly(ADP-ribose) polymerase, a chromatin-bound enzyme, catalyzes postsynthetic modifications of various nuclear proteins through the covalent attachment of ADP-ribose units at the expense of the cellular NAD pool [1-3]. Poly(ADP-ribosylation) appears to be involved in DNA excision repair, cellular proliferation, and differentiation [1-3] and has been shown to induce architectural changes in chromatin [4-6]. 

Xiang ZH, Cao DP, Wang WC et al (2012) Postsynthetic lithium modification of covalent-organic polymers for enhancing hydrogen and carbon dioxide storage. J Phys Chem C 116 5974-5980... 

Wang Z, Cohen SM (2007) Postsynthetic covalent modification of a neutral metal-organic framework. J Am Chem Soc 129 12368-12369... 

Wang Z, Tanabe KK, Cohen SM (2010) Tuning hydrogen sorption properties of metal-organic frameworks by postsynthetic covalent modification. Chem Eur J 16 212-217... 

Liu, B., Ma, M. Y, Zacher, D., Betard, A., Yusenko, K., Metzler-Nolte, N., Woll, C., and Fischer, R. A. Chemistry of SURMOFs Layer-selective installation of fimctional groups and postsynthetic covalent modification probed by fluorescence microscopy. J Am Chem Soc 133, 1734-1737 (2011). 

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