3-Abz (m-aminobenzoic acid) can be considered a γ-amino acid. Incorporation of m-aminobenzoic acid into peptide chains generates a rigid turn.
Amino acids are molecules containing an amine group, a carboxylic acid group and a side chain that varies between different amino acids. These molecules contain the key elements of Carbon, Hydrogen, Oxygen, and Nitrogen. These molecules are particularly important in biochemistry, where this term refers to alpha-amino acids with the general formula H2NCHRCOOH, where R is an organic substituent. In an alpha amino acid, the amino and carboxylate groups are attached to the same carbon atom, which is called the α–carbon. The various alpha amino acids differ in which side chain (R group) is attached to their alpha carbon. These side chains can vary in size from just a hydrogen atom in glycine, to a methyl group in alanine, through to a large heterocyclic group in tryptophan.
t-Butyloxycarbonyl (Boc) is an acid-labile temporary Nα-protecting group employed in solution synthesis and in SPPS (Boc/Bzl-based SPPS). Common cleavage reagents are TFA/methylene chloride (1:1), HCl in ethyl acetate or dioxane, 98% formic acid.
See also ivDde and Dmab.
Unlike Hmb amino acids/dipeptides, Dmb derivatives cannot form benzo-oxazepinones during activation.
- Drug Master File
Excitation 490 nm, emission 520 nm.
An acyl group often N-terminally introduced, formyl is more polar than acetyl (Ac). A permanent modification of a peptide.
Ser/Thr(Gal/GalNAc)-peptides are best obtained by Fmoc-SPPS, as the O-glycosyl bond is acid-labile.
Gla-containing peptides are best obtained by Fmoc-SPPS, as Gla tends to decarboxylate yielding Glu in the presence of strong acids.
Ser/Thr(Glc/GlcNAc)-peptides are best obtained by Fmoc-SPPS, as the O-glycosyl bond is acid-labile.
Activated Har derivatives show a far lower tendency for lactamization than the corresponding Arg derivatives.
Contrary to Cys derivatives, Hcy derivatives do not tend to racemize during coupling nor to β-elimin.
As proline residues strongly influence the conformation of a peptide, replacement of Pro by Hpr (or azetidine-2-carboxylic acid (Aze)) can modulate its secondary structure.
O-protection of Hyp during Fmoc-SPPS is recommandable but not absolutely mandatory. The secondary hydroxyl function is somewhat more accessible than the Thr hydroxyl moiety.
Peptide N-ethylamides resist degradation by carboxypeptidases.
See also Dde, ivDde.
PACAP is an important regulator of endocrine and homeostatic processes, such as secretion of pituitary and gut hormones and food intake.
Whereas D-Penicillamine is a precursor of penicilline and used as a drug, the L-enantiomer is toxic. In peptides, Pen is incorporated as a Cys replacement in disulfide bridges.