Lecture 10 Part 2 Flashcards
what occurs when there is an AA deficiency
- poor growth
- reduced milk and egg production
- anorexia
- infertility
absorption of proteins and AAs during 1st 24 hours after birth
- large proteins
- immunoglobins from colostrum
- these large particles wont be able to be digested after first 24 hours
absorption after 24 hours
proteins digested and absorbed as AAs and peptides
digestion of proteins
- begins in gastric stomach
- small intestine (pancreatic region) that gives products of free AA, dipeptides, and tripeptides
pepsinogen + HCL=
pepsin
what hydrolyzes peptide bonds between specific AAs
Pro carboxypeptidase–> carboxypeptidase
absorption of AAs and peptides
- occurs in small intestine
- free AAs absorbed by active transport systems
- absorption rate vary
ruminant absorption of AAs and peptides
may also occur in rumen and omasum
where are dipeptides and tripeptides absorbed
- into mucosal cells
- hydrolyzed to FAA before entering circulation
what are AAs used for
- tissue protein synthesis
- synthesis of enzymes, hormones, other metabolites
- transamination-AA biosynthesis
- deamination and use of carbon skeleton for energy
tissue protein synthesis
- occurs in every cell of body, hormonal control
- takes place at ribosome
- requires tRNA, rRNA, mRNA, DNA
tRNA
caries specific AA and base pairs with mRNA
rRNA
part of ribosome
mRNA
determines AA sequence of a protein
- codons of 3 nucleotides
DNA
genetic code
tissue protein degradation
- breakdown of proteins
- fate of AAs from protein degradation
breakdown of proteins
- requires proteases
- breakdown to AAs
- stimulated by glucocorticoids
what are the fate of AAs from protein degradation
- used in synthesis of protein
- broken down to NH2 and carbon skeleton if body needs energy
what are the 2 processes in AA breakdown
- deamination
- transamination
deamination
- NH2 removed—> ammonia
- ammonia disposed thru urea cycle
- C skeleton–> keto acid, or gluconeogenesis, or ketogenesis
transamination
- resynthesis of AA
- transfer NH2 from AA–>keto acid—>NEAA
- C skeleton—>keto acid, or gluconeogenesis, or ketogenesis
what are strictly ketogenic
leucine and lysine
why do some AAs have different fats
due to structural uniqueness
urea cycle
- excretion of excess N
- occurs in kidney and liver
- several complex steps
- energy expending
