Glycine hydroxylation

Now, it is seen that polar groups dominate the molecular structure, resulting from hydroxyl groups from the two serine and threonine fragments in addition to the peptide bonds themselves. Only weak dispersive interactions will be contributed by glycine fragments (CH2 groups). 

A number of peptide hormones have a carboxyl terminal amide which is derived from a glycine terminal residue. This glycine is hydroxylated on the a-carbon by a copper-containing enzyme, peptidylglycine hydroxylase, which, again, requires ascorbate for reduction of Cu ". ... 

Other hydroxylic solid-phase supports such as cross-linked agarose are similarly activated with CDI or V V -carbonyldi-1,2,4-triazole. The activated matrices can then be smoothly coupled with AT-nucleophiles such as glycine, 6-aminohexanoic acid, diamines, or proteins. 212 ... 

The SPSS following this route is illustrated in Scheme 5. In the first step, Fmoc-protected glycine is attached to a trityl-derived hydroxyl... 

A thioglycoside was immobilized by the following sequence of reactions. Treatment of the dibutyltin acetal of diol 36 with succinic anhydride afforded 37 in an excellent yield of 85%. Attachment of Fmoc protected glycine to TentaGel hydroxyl resin (38, 0.37 mmol/g resin) under standard conditions followed by removal of the Fmoc group by treatment with piperidine gave polymer 27. Compound 37 was immobilized by amide bond formation with 27 in the presence of... 

The many (possibly more than 30) types of collagens found in human connective tissues have substantially the same chemical structure consisting mainly of glycine with smaller amounts of proline and some lysine and alanine. In addition, there are two unusual amino acids, hydroxyproline and hydroxylysine, neither of which has a corresponding base-triplet or codon within the genetic code. There is therefore, extensive post-translational modification of the protein by hydroxylation and also by glycosylation reactions. 

An unusual method for chain termination is utilized in the biosynthesis of myxothiazol and melithiazol. The domains in the terminal modules of these synthetases are arranged in the following order C-A-MOx-A-PCP-TE (MOx = monooxygenase domain). In the termination modules of these synthetases, the MOx domain likely catalyzes hydroxylation of the ct-carhon of the C-terminal glycine residue of the requisite peptidyl-5-PCP. The resulting intermediate then undergoes spontaneous conversion into PCP-bound glyoxylic acid and a terminal amide. This sequence yields the final product in the case of myxothiazol, whereas the terminal amide is transformed to a methyl ester to complete melithiazol biosynthesis. 

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