ANS 4445- module 1 pt.2: amino acids and proteins

exam 3 content

how are nonessential amino acids (NEAAs) and essential amino acids (EAAs) classified?

based upon if they’re needed in the diet or not

what are essential amino acids (EAAs)?

indispensable AAs

AAs the body can’t synthesize the AA

AAs that need to be supplied in the diet

what are nonessential amino acids (NEAAs)?

dispensable AAs

AAs the body can synthesize to meet the requirement

AAs not required in the diet

what are other conditions that make AAs essential?

age, stress, feed ingredients, feed processing methods

what are the 10 EAAs?

phenylalanine

valine

threonine

tryptophan

isoleucine

methionine

histidine

arginine

lysine

leucine

what are the aromatic AAs?

phenylalanine, tryptophan, tyrosine

essential AAs, used for protein synthesis

what is tyrosine?

an aromatic AA

synthesized from phenylalanine

regulates growth and development

component of thyroid hormone

what are the branched chain AAs?

valine, leucine, isoleunce

essential AAs

why are branched chain AAs important?

they play a role in energy regulation, gut health, and diseases in animals

val, leu, ile share a common pathway for metabolism

excess supplementation of leu reduces the levels of ile and val

what are the sulfur-containing AAs?

cysteine and methionine

information about cysteine and methionine

sulfur-containing AAs

met can be synthesized from cys but not in humans and some other animals

• essential AA

cys is a NEAA

• can form a disulfide bridge

what are the non-essential amino acids?

glycine

serine

glutamic acid

taurine

alanine

aspartic acid

tyrosine

proline

glutamine

cysteine

what are the conditionally essential amino acids?

glycine

serine

cysteine

tyrosine

proline

glutamine

information about glycine

a limiting AA for broiler chickens during the starter phase

synthesized in vivo from threonine and serine

chickens endogenously synthesize, but 40% of the total requirement of the AA needs to be provided in the diet

causes chickens to have 11 EAAs

information about proline

NEAA

considered an EAA in hens

accretion was found to be frome diet

information about arginine

important during development

prevents development of several diseases and physiological disorders

can be synthesized from other AAs (choline, serine, hydroxyproline, threonine)

requirement higher in young animals and humans than in matured

information about glutamine

NEAA

strengthens intestinal mucosa during illness

becomes essential during illness or stress

what are protein-carbohydrates?

glycoproteins

AAs in the polypeptide chains accept sugars

ex.) mucoproteins

what are protein-lipids?

complexes that include membrane proteins in animal cells

myelin found in the nervous system as a sheath around nerve fibers

what is transcription?

1 DNA strand makes up a non-coding strand

acts as a template for the synthesis of a complementary RNA strand by RNA polymerase

what is a non-coding strand?

a DNA strand that makes up a gene

used in transcription

what is the primary transcript?

the complementary RNA strand synthesized by RNA polymerase in transcription

what is translation?

then sequence of mRNA being decided to build the AA sequence of a polypeptide

what is the process of protein synthesis?

DNA in the cell gives mRNA the instructions

mRNA goes into the cellular fluid and attaches to ribosomes

tRNA carries free AAs to the mRNA

ribosomes move along mRNA

• allows enzymes to bond 1 AA to another until the completed protein is finished and released

what is denaturation?

loss of biological activity

caused by: pH, temp, ionic strength, solubility

what is renaturation?

a regain of biological activity

what is the cycle of protein denaturation?

denaturation → denatured protein → renaturation → normal protein

what is the process of protein digestion?

stomach releases HCl → denatured protein strands

HCl converts inactive form of pepsinogen into active form pepsin

pepsin breaks the proteins into smaller peptides

why is protein digestion necessary?

dietary protein needs to be broken down to release AAs

what is pepsin?

an important digestive enzyme for proteins

the active form of pepsinogen, converted from pepsinogen by HCl

how much of protein weight do amino nitrogen make up?

about 16% of the weight

nitrogen content * 6.25 = protein content of foods or tissue

what do you determine in your food?

for feeds/diets → just the N content

N * 6.25 = crude protein

what is protein turnover?

2 sources of free amino acid pool, endogenous and exogenous sources

endogenous vs. exogenous protein

endogenous protein: protein obtained from the body tissues (anabolism)

exogenous protein: protein obtained from the breakdown of food (catabolism)

what is nitrogen balance?

relates nitrogen input to nitrogen output

positive or negative

positive vs. negative nitrogen balanced

positive nitrogen balance: during growth or when building new tissue

• increase in the total pool of body protein

negative nitrogen balance: if burned, fever, injury, infection, or starvation

• more protein is excreted from the body → less total pool of body protein

what happens to excess AAs consumed or unable to be used by the body?

they aren’t stored

degraded into ureu, uric acid, and creatinine

lost in feces or sweat