Chapter 27 - Amino Acids and Proteins

Peptide bonds

Peptide bonds

________ are formed by activating a carboxyl group for nucleophilic attack by an amino group with reagents such as carbodiimides.

Peptide synthesis

________ necessitates the protection of the amino group of one amino acid and the carboxyl group of the other so that only the necessary coupling occurs.

bond angles

The ________ between the amide nitrogen and the amide carbonyl carbon are around 120°.

Electrophoresis

________ is the technique of separating substances in an electric field based on their charge.

amide bonds

All of the ________ are hydrolyzed in acid, and the individual amino acids present are separated and quantified using chromatography.

polypeptide chain

When the synthesis is finished, the ________ is freed from the solid support by benzyl ester linkage cleavage.

amino acid sequencing

A polypeptide or protein's main structure can be identified directly by fragmenting the protein using cyanogen bromide and enzymes, followed by ________ of the resultant fragments.

BOC

Carbamates, such as the Z (benzyloxycarbonyl) or ________ (tert- butyloxycarbonyl) groups that are eliminated in acid, are the most frequent amino- protecting groups.

amide link

The ________ produced between a- amino acids is known as a peptide bond.

Tertiary

________ (3°) structure is the overall folding pattern and spatial arrangement of all atoms in a single polypeptide chain.

planarity

The ________ is caused by resonance with the amide N atom.

Edman degradation

The ________ can be repeated and automated to identify the sequence of up to 20 to 30 N- terminal amino acids.

enzymes

Protein- cleaving ________ like trypsin and chymotrypsin break between certain amino acids, resulting in specific pieces.

biological macromolecule

A polypeptide is a(n) ________ made up of numerous amino acids that are linked together by peptide bonds.

solid phase synthesis

In ________, or polymer- supported synthesis of polypeptides, the C- terminal amino acid is joined to a chloromethylated polystyrene resin as a benzyl ester.

hydrophobic effect

The ________ is the aggregation of hydrophobic groups inside proteins produced by their exclusion from water.

Amino acids

________ are substances that have an amino group as well as a carboxyl group.

complementary hydrophobic patches

The hydrophobic effect, in which ________ on each interacting partner contact each other, is a major factor stabilizing the ordered assembly of proteins into specific quaternary structures, providing a driving force for assembly by relieving unfavorable contacts of the hydrophobic patches with water.

Edman degradation

The ________ removes and identifies the N- terminal amino acid of peptides or proteins using phenyl isothiocyanate.

peptide bond

A(n) ________ is planar, which means that the four atoms of the amide and the two a- carbons of the ________ are in the same plane.

hydrophobic effect

The ________ is the aggregation of hydrophobic groups inside proteins.

amino acids

18 ________ are (S)- ________ in the R, S convention.