Hydroxylated amino acid residues

Cyclic peptides are important biologically active compounds that combine peptide properties with conformational bias and often improved serum stability and membrane penetration [1-3]. Depsipeptides are similar compounds, but they contain as part of their backbone one or more hydroxylated amino acid residues that add ester or lactone moieties to the peptide (Fig. 1) [4-6]. Cyclo- and... 

Table IV. Hydroxylated Amino Acid Residues Found in Proteins...

Pregnenolone is transported from the mitochondria to the ER, where a hydroxyl oxidation and migration of the double bond yield progesterone. Pregnenolone synthesis in the adrenal cortex is activated by adrenocorticotropic hormone (ACTH), a peptide of 39 amino acid residues secreted by the anterior pituitary gland. 

Staphylococcal nuclease (SNase) is a single-peptide chain enzyme consisting of 149 amino acid residues. It catalyzes the hydrolysis of both DNA and RNA at the 5 position of the phosphodiester bond, yielding a free 5 -hydroxyl group and a 3 -phosphate monoester... 

Sakwe, A.M. and Titanji, V.P.K. (1997) Evidence for increased hydroxylation of pyrrolidone amino acid residues in the cuticle of mature Onchocerca volvulus. Biochimica et Biophysica Acta- Molecular Basis of Disease 1360, 196-202. 

Hydroxyl radicals are the most reactive free-radical species known and have the ability to react with a wide number of cellular constituents including amino-acid residues, and purine and pyrimidine bases of DNA, as well as attacking membrane lipids to initiate a free-radical chain reaction known as lipid peroxidation. 

Parallel synthesis of 62 different fucosylated tripeptides resulted in two ligands with submicromolar affinity for the P-selectin however, the desired activity for the E-selectin was not observed.98 For the E-selectin selectivity, it was necessary to incorporate a hydroxyl group that mimics the 4-hydroxyl of the central Gal in SLex in addition to a Fuc-residue and a carboxylate to obtain ligands with > 10-fold increased activity over that of the SLex tetrasaccharide.81 One of the best ligands was obtained from Thr(a-Fuc)-OEt, which was first /V-acylated with a hydroxyl amino acid and then elongated with a di-acid to furnish the acid mimic of the sialic acid carboxylate (Fig. 14.4). This approach was further developed as a solid-phase method where the molecule was linked to a solid support through the invariable fucosyl moiety.99... 

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