Biochem Lec - Proteins

Proteins

Most abundant and functionally diverse molecules in living systems

Peptide bonds – Amide bonds

Bonds that link amino acids together.

flagella (made of flagellin), cilia, muscles

Motion and locomotion of cells and organisms

hemoglobin

Transport of materials in body fluids

Acylation

process of introducing an acyl group (R–CO–) into a molecule, often replacing a hydrogen atom

Amidation

Formation of an amide by reacting a carboxylic acid (or derivative) with an amine

Esterification

Formation of an ester by reacting a carboxylic acid with an alcohol

Formation of amides

The creation of amides by reacting carboxylic acids (or derivatives like acyl chlorides) with amines

Acid anhydrides

wo carboxylic acid molecules (or derivatives) combine, releasing water and forming an acid anhydride (R–CO–O–CO–R)

Ninhydrin Test

Test for alpha amino acids

Deep Purple Color

Positive Result for ninhydrin Test

Biuret Protein Test

Test for Polypeptides or large proteins

Purple Color

Positive Result for Biuret Protein Test

Xanthoprotein Test

Test for aromatic amino acids

Yellow complex

Positive Result for Xanthoprotein Test

Disulfide Bridge Test

indicates the presence of disulfide bonded cysteine

PbS - Black precipitate

Positive Result for Disulfide Bridge Test/Lead acetate test