M7: Proteins and Amino Acids

Amino Acids

Are organic compounds containing an Amino group and a Carboxyl group

Polypeptides

Proteins consists of one or more chains of amino acids called _________

Genes

The amino acid sequences of proteins are encoded in the ___________

a-Amino Acids

The 20 common amino acids that make up proteins in the body are mostly __________

L-isomers

All the amino acids in the body are __________

R group

(Side chain) that gives each amino acid its identity

Biomolecules

Proteins, Carbohydrates, Lipids, Nucleic acids

Polymers

Comprised of repeating units of Monomers

Zwitterionic

Is a molecule with both positive and negative formal charges

Cationic

Acidic Conditions

Anionic

Basic Conditions

Lysine

__________ can have different states of protonation and deprotonation depending on the pH

Biuret Test

The General Test for Proteins

Biuret Test

[+] Purple /Violet Solution; Presence of 2 or more peptide bonds

Result of Gelatin in Biuret Test

[+] Purple/Violet Solution; Presence of 2 or more Peptide Bonds

Result of Egg Albumin in Biuret Test

[+] Purple/Violet Solution; Presence of 2 or more Peptide Bonds

Ninhydrin Test

It is the test for the presence of a-Amino Acid in Proteins

[+] Blue violet Solution; Presence of a-Amino Acid (Except: Proline [+] Orange Solution)

Xanthoproteic Test

It is the test for the presence of Aromatic Amino Acids

[+] Yellow/ Orange yellow Solutin; Presence of Tyrosine, Tryptophan, Phenylalanine

Millon’s Test

It is the test for Phenolic compounds. It is also used to detect the presence of Tyrosine, which is the only amino acid containing a phenol group.

Millon’s Test

[+] Brick Red precipitate; Presence of Tyrosine, and Phenol containing compounds

Hopkins- Cole Test

It is a test for the presence of Tryptophan, which is the only amino acid containing an indole group.

Hopkins-Cole Test

[+] Violet Ring at the Junction; Presence of Tryptophan

Lead Sulfide Test

It is a test for the presence of Sulfhydryl containing amino acid (Cysteine and Methionine)

Lead Sulfide Test

[+] Black Precipitate; Pbs

[+] Cysteine and Methionine

Glutathione

Is made up of Glutamic acid, Cysteine and Glycine