Amino Acids and Lipids Part 1

how many amino acids are there

20

Amino acids are linked by...

Peptide bonds

Dipeptide amino acid count

2

Tripeptide amino acid count

3

Oligopeptide amino acid count

3-30

Peptide amino acid count

Less than 50

Protein amino acid count

More than 50

Alpha amino acids consist of over ____ compounds

300

How many alpha amino acids are considered the monomeric units of protein?

20

Two forms of alpha carbon chiral centers

D and L

When the R group is -H, the amino acid is...

Glycine

When the R group is -CH3, the amino acid is...

Alanine

The two simplest amino acids are...

Glycine and alanine

Amino acids are... (z)

Zwitterions

What is a zwitterion?

Compounds with an equal number of ionizable groups of opposite charge resulting in no net charge

Most amino acids have no net charge- T or F

True

Carboxyl groups are acidic or basic?

Acidic

Carboxyl group pK

2-3

Amine groups are acidic or basic?

Basic

Amine group pK

9-10

Chemical classifications of amino acids (7)

Aliphatic, hydroxyl, sulfur, acidic/ amides, basic, aromatic, imino

Aliphatic amino acids (5)

Isoleucine, leucine, valine, glycine, alanine

Which aliphatic amino acids are also branched chain amino acids? (3)

Isoleucine, leucine, valine

Hydroxyl amino acids (3)

Serine, threonine, tyrosine

Sulfur amino acids (2)

Cysteine, methionine

2 cysteines linked in a disulfide bond is what

cystine

cysteine formed from what

methionine

Acidic/ amide amino acids (4)

Aspartate, asparagine, glutamate, glutamine

Basic amino acids (3)

Arginine, lysine, histidine

Aromatic amino acids (4)

Histidine, phenylalanine, tyrosine, tryptophan

Imino amino acids (1)

Proline

Post-translational modification of proline is...

Hydroxyproline

Taurine is an amino acid- T or F

False

Why is taurine needed? (4)

Needed for bile salts, antioxidants, cell membranes, electrolyte balance

Cats lack the enzyme necessary to produce...

Taurine

A taurine deficiency in cats can lead to... (4)

Retinal degeneration, blindness, dilated cardiomyopathy, reproductive failure

Amino acids synthesize...

Proteins

Amino acid energy source

Remove amine group, oxidize carbon skeleton

Secondary amino acid function examples (4 AA)

Histidine, cysteine, tyrosine, tryptophan

Histidine secondary function

Histimine

Cysteine secondary function

Glutathione (tripeptide, antioxidant)

Tyrosine secondary function

Catecholamines (epinephrine), thyroid hormones

Tryptophan secondary function

Serotonin and melatonin

essential amino acids

PVT TIM HALL

phenylalanine

valine

threonine

tryptophan

isoleucine

methionine

histidine

arginine

leucine

lysine

what amino acids are synthesized from other amino acids

cysteine and tyrosine

Requirements for these two amino acids decrease in adults

Arginine and histidine

Semiessential amino acids

Arginine and histidine

Average amino acid has what percent nitrogen?

16

Average amino acid metabolizable energy

4kcal/ g

Amino acid with lowest nitrogen

Tyrosine 7.7%

Amino acid with most nitrogen

Arginine 32.2%

Amino acid with lowest metabolizable energy

Glycine 1.6kcal/ g

Amino acid with highest metabolizable energy

Phenylalanine 6.1kcal/ g

Nonruminant mammals require how many amino acids in the diet?

20

Arginine is made in nonruminant animal urea cycles, but why is it still required in the diet?

Nonsufficient amount is produced

Bird amino acid requirements

20 amino acids plus glycine and serine

Arginine requirement in birds vs nonruminant mammals

Birds> nonruminant mammals (birds don't have the urea cycle)

Ruminant amino acid requirement

Rumen microorganisms can synthesize amino acids from a nitrogen source

Essential amino acid derived proteins

Protein synthesis is specific for a particular amino acid

Catalytic protein- enzyme

Pepsin

Contractile protein- muscle

Myosin, actin

Gene expression protein- histones

H1

Hormone protein

Insulin

Protection protein

Immunoglobulins, interferon

Regulatory protein

Calmodulin

Nutrient storage protein

Ferritin, metallothionein, myoglobulin

Structural protein

Collagen

Transport protein

Albumin, hemoglobin

Amino acids link together through which type of bonds

Peptide

Protein primary structure

Order of amino acids

Protein secondary structure

Interactions of amino acids close to each other in the protein (alpha helix)

Protein tertiary structure

Interactions of amino acids in different regions of the protein

Protein quaternary structure

Interactions between amino acids in separate protein chains

Amino acid interactions that contribute to secondary, tertiary, and quaternary structure

Hydrogen bonding, electrostatic interaction, hydrophobic interaction, disulfide bridges

Hydrogen bonding in amino acids

Overlap of hydroxyl containing amino acids such as serine, threonine, and tyrosine

Electrostatic interaction in amino acids

Acidic (-) and basic (+), aspartate and lysine

Hydrophobic interaction in amino acids

Hydrophobic regions of aliphatic or aromatic amino acids

Disulfide bridge in amino acids

2 cysteines

Examples of amino acid modifications on protein function

Hemoglobin and sickle cell anemia, growth hormone (somatropin), insulin

Hemoglobin and sickle cell anemia amino acid modification

Single amino acid substitution

Growth hormone somatropin amino acid modifications

Species differences

Single amino acid substitution specifics- hemoglobin

2 alpha subunits, 2 beta subunits

Single amino acid substitution specifics- sickle cell anemia

Defect in beta subunit, valine on position 6 instead of glutamate

Sickle cell anemia facts

Autosomal recessive, protection against malaria, homozygote, reduced life span

Growth hormone somatropin amino acid count

191 amino acid protein hormone

Insulin amino acid count

51 amino acids, 21 alpha chain, 30 beta chain

Insulin in which two species works in humans

Bovine and porcine

Structure of amino acid linkage determines...

Shape of protein

Shape of protein determines...

Function

Protein turnover

Protein synthesis and degradation occur constantly

Protein accretion

Synthesis - degradation

Positive nitrogen balance

Synthesis > degradation

Negative nitrogen balance

Synthesis < degradation

Zero nitrogen balance

Synthesis = degradation

Amino acid requirements are affected by

Growth rate, age, level of production, gender, genotype, other physiological changes

Amino acid requirements are determines by the types and amounts of proteins being synthesized- T or F

True

Muscle protein

Myosin, actin

Pancreas protein

Insulin, glucagon

Liver protein

Albumin, ferritin

Intestine protein

Pepsin, lactase