Amino Acids - Structure, full name, & acidity

ALA

ALA - Alanine Nonpolar, aliphatic R Groups: pK1(-COOH): ~2.34 and pK2(-NH3+): ~9.60 Tend to cluster together on the inside of proteins, stabilizing protein structure via hydrophobic interactions.

ARG

ARG - Arginine Positively charged R groups - Basic pK1(-COOH): ~2.1 and pK2(-NH3+): ~9.3 **pK3 (=NH2+): 6.00

ASN

ASN - Asparagine Polar, uncharged R groups: H bonds with water pK1(-COOH): ~2.1 and pK2(-NH3+): ~9.3

ASP

ASP - Aspartate Negatively charged R groups - Acidic pK1(-COOH): ~2.1 and pK2(-NH3+): ~9.3 **pK3 (-COOH): 3.65 ** Second carboxyl group with a net negative charge at pH 7.0.

CYS

CYS - Cysteine Polar, uncharged R groups: H bonds with water pK1(-COOH): ~2.1 and pK2(-NH3+): ~9.3 ** pK3 (-SH): 8.18 **Pairs of cysteines can oxidize through a disulfide bonds to form cystine, which is non-polar and strongly hydrophobic.

GLN

GLN - Glutamine Polar, uncharged R groups: H bonds with water pK1(-COOH): ~2.1 and pK2(-NH3+): ~9.3

GLU

GLU - Glutamate Negatively charged R groups - Acidic pK1(-COOH): ~2.1 and pK2(-NH3+): ~9.3 **pK3 (-COOH): 4.25 ** Second carboxyl group with a net negative charge at pH 7.0.

GLY

GLY - Glycine Nonpolar, aliphatic R Groups: pK1(-COOH): ~2.34 and pK2(-NH3+): ~9.60

HIS

HIS - Histidine Positively charged R groups - Basic pK1(-COOH): ~2.1 and pK2(-NH3+): ~9.3 **pK3 (-NH): 12.48 **His is the only amino acid with an ionizable side chain that has a pKa near neutrality. Therefore, His can serve as a proton donor or acceptor in many enzyme-catalyzed reactions Phosphorylation by ATP for reversible covalent modification enzyme regulation

ILE

ILE - Isoleucine Nonpolar, aliphatic R Groups: pK1(-COOH): ~2.34 and pK2(-NH3+): ~9.60 ***ESSENTIAL ***Chiral side chain Tend to cluster together on the inside of proteins, stabilizing protein structure via hydrophobic interactions.

LEU

LEU - Leucine Nonpolar, aliphatic R Groups: pK1(-COOH): ~2.34 and pK2(-NH3+): ~9.60 Tend to cluster together on the inside of proteins, stabilizing protein structure via hydrophobic interactions. ***ESSENTIAL

LYS

LYS - Lysine Positively charged R groups - Basic pK1(-COOH): ~2.1 and pK2(-NH3+): ~9.3 **pK3 (-NH3+): 10.53 ***HIGHEST OCCURRENCE IN PROTEINS Acetylation by (acetyl-coA) or ubiquitination for reversible covalent modification enzyme regulation

MET

MET - Methionine Nonpolar, aliphatic R Groups: pK1(-COOH): ~2.34 and pK2(-NH3+): ~9.60 ***ESSENTIAL

PHE

PHE - Phenylalanine Aromatic R groups: pK1(-COOH): ~2.34 and pK2(-NH3+): ~9.60 ***ESSENTIAL

PRO

PRO - Proline Nonpolar, aliphatic R Groups: pK1(-COOH): ~2.34 and pK2(-NH3+): ~9.60

SER

SER - Serine Polar, uncharged R groups: H bonds with water pK1(-COOH): ~2.1 and pK2(-NH3+): ~9.3 Phosphorylation by ATP for reversible covalent modification enzyme regulation

THR

THR - Threonine Polar, uncharged R groups: H bonds with water pK1(-COOH): ~2.1 and pK2(-NH3+): ~9.3 ***Chiral side chain Phosphorylation by ATP for reversible covalent modification enzyme regulation

TRP

TRP - Tryptophan Aromatic R groups: pK1(-COOH): ~2.34 and pK2(-NH3+): ~9.60 ***ESSENTIAL ***LOWEST OCCURRENCE IN PROTEINS

TYR

TYR - Tyrosine Aromatic R groups: pK1(-COOH): ~2.34 and pK2(-NH3+): ~9.60 **pKr(-OH): 10.07 The hydroxyl group can form hydrogen bonds and plays an important functional role in some enzymes Phosphorylation or Adenylation by ATP for reversible covalent modification enzyme regulation

Essential Amino Acids

The Whole Food Ladder Must Have Various Key Ingredients threonine, tryptophan, phenylalanine, leucine, methionine, histidine, valine, lysine, and isoleucine.

VAL

VAL - Valine Nonpolar, aliphatic R Groups: pK1(-COOH): ~2.34 and pK2(-NH3+): ~9.60 Tend to cluster together on the inside of proteins, stabilizing protein structure via hydrophobic interactions. ***ESSENTIAL