AMINO ACIDS (NEW)

- Livy

Amino Acids

20 are coded in DNA out of 300 different types

Optically Active

Property shown by all amino acids except glycine due to presence of a chiral center

Glycine

The only amino acid that is not optically active because it has H as its R group

Chiral Carbon

A carbon with four different substituents that gives rise to optical activity

Chiral Center

Located between nitrogen and carbon in amino acids

L-amino acid

The type of amino acids found in proteins

Levorotatory

Rotates right to the left

Dextrorotatory

Rotates left to the right

Codeine

An antitussive drug used for dry cough and is derived from opium; addictive

Dextromethorphan

A drug used in place of codeine to reduce the addictive effects (e.g., in Vicks Formula 44)

Cetirizine

An antihistamine that can cause drowsiness

Levocetirizine

An antihistamine with no drowsiness side effect

Polarimeter

An instrument used to measure optical activity

Zuitter Ion

A molecule that coexists with both positive and negative charges (neutral overall)

Alanine (A)

Methyl

Cysteine (C)

Thiol/Mercapto

Aspartate (D)

Carboxymethyl

Glutamate (E)

Carboxyethyl

Phenylalanine (F)

Phenyl

Glycine (G)

H

Histidine (H)

Imidazole

Isoleucine (I)

Sec-butyl

Lysine (K)

Butylamine

Leucine (L)

Isobutyl

Methionine (M)

Methylthioethyl

Asparagine (N)

Methylcarboxyamide

Pyrrolysine (O)

Butylamide + Pyrrole

Proline (P)

Azacylocpentane

Glutamine (Q)

Ethylcarboxyamide

Arginine (R)

Propylguanidine

Serine (S)

Hydroxymethyl

Threonine (T)

Hydroxyethyl

Selenocysteine (U)

Selenothiol

Valine (V)

Isopropyl

Tryptophan (W)

Indole

Tyrosine (Y)

Phenol

Pyrrolysine & Selenocysteine

Amino acids currently under investigation

Proline

Has an imino acid group and is used to synthesize collagen

Serine & Threonine

Alcoholic amino acids

Thiol

Refers to sulfur-containing amino acids

Phenylalanine, Histidine, Tryptophan, Tyrosine

Amino acids with cyclic structures

Glucogenic

Amino acids that can be converted to glucose via gluconeogenesis

Ketogenic

Amino acids that can be converted to ketone bodies

Both Glucogenic and Ketogenic

Amino acids that can be converted to either glucose or ketone bodies

Gluconeogenesis

Process of glucose creation from non-sugar sources; occurs in the cytoplasm during starvation or hunger state

Ketogenesis

Process of ketone production from amino acids; occurs in the mitochondria

Leucine and Lysine

The only amino acids that are exclusively ketogenic

Phe, Ile, Trp, Tyr, Thr

Amino acids that are both glucogenic and ketogenic

Glucogenic Amino Acids

All amino acids except leucine and lysine

Polar

Amino acids with zero net charge at neutral pH and contain dipole moment due to electronegative elements like oxygen, sulfur, or nitrogen

Non-polar

Amino acids made of hydrocarbons that do not bind or participate in ionic bonding

Electrically Charged

Amino acids that are either acidic or basic, depending on their charge at neutral pH

Acidic

Electrically charged amino acids that are proton donors and negatively charged at neutral pH

Basic

Electrically charged amino acids that are proton acceptors and positively charged at neutral pH

Brønsted–Lowry

Theory defining acids as proton donors and bases as proton acceptors

Lewis

Theory defining acids as electron acceptors and bases as electron donors

Arrhenius

Theory defining acids as substances that produce H⁺ and bases as those that produce OH⁻ in solution

pH

Stands for “power of hydrogen,” calculated as the negative logarithm (–log) of hydrogen ion concentration

Isoelectric Form (pI)

The pH at which the net charge of a molecule is zero

pl = (pk1 + pk2) / 2

Formula of Isoelectric Form

Acidic Amino Acid

Reaches isoelectric point in an acidic medium (net charge = 0)

Basic Amino Acid

Reaches isoelectric point in a basic medium

Bond Formation

Occurs through a dehydration reaction between amino acids

Peptidyltransferase

facilitates transfer of peptides (translation)

Peptide Bond

A bond formed between the carboxyl group of one amino acid and the amino group of another

Amide

Functional group formed in peptide bonds