Proteins and their digestion Flashcards
Where do proteins begin to breakdown?
in the stomach (other than the mechanical breakdown by the teeth)
What enzyme is released in the stomach to breakdown proteins?
pepsin
(suffix) -ogen
zymogen form
prefix -pro
zymogen form
HCL is released by ______ and its job is
gastric partial cells, denatures the proteins to make them easier for pepsin to cleave
pepsinogen
secreted by child cells in the stomach, zymogen form of pepsin, HCL converts into pepsin
Pepsinogen + H+ —–>
Pepsin
Trypsinogen + enteropeptidase —->
Trypsin
Chymotrypsinogen + Trypsin —->
Chymotrypsin
Proelastase + Trypsin —->
Elastase
Procarboxypeptidases + trypsin —->
Carboxypeptidases
Pancreas secretes what so what can function?
secretes enzymes and bicarbonate ions to neutralize the acidic chyme so the enzymes can function
Pancreatic proteases are all release as _______ so they _____
zymogens, don’t digest each other
activated enzymes in the intestine causes what
proteins to be broken down into di- and tai-peptides
Enzymes are specific. This means that they
will only digest individual aa’s, each has specificity for peptide bonds between different aa’s in the polypeptide chains
what finishes proteolytic cleavage to aa’s
exopeptidase (in the brush border within the intestinal cells)
absorption of aa’s
by secondary active transport with sodium ions
how many different amino acid transporters are there?
6
proteins is the only macronutrient that contains?
Nitrogen
we can or cannot store extra protein
cannot
all protein is
functional protein
blood collection tube colours
red and lavender
red tops
contains no anticoagulant - used for serum
Lavender tops
contain K+ salt of RRDTA - chelates Ca+, does not allow blood to coagulate, used for plasma or whole blood
Whole blood
red fluid drawn from our veins, contain anticoagulant (plasma) or not (serum)
Plamsa
Protein-containing fluid portion of blood, after centrifugation to remove red and white blood cells and platelets
Serum
Clear fluid left after blood is allowed to clot and then centrifuged - plasma minus the blood clotting proteins
Albumin
most abundant blood protein, made in the LIVER (as are many other blood proteins), 60% of total plasma protein, contributes 70-80% of total osmotic pressure of plasma
Albumin bind to what in many drugs?
fatty acids
low albumin levels (malnutrition or cirrhosis of the liver )
drug dosage will need adjusted since the effects the amount of free drug in the body as well as half-life of the drug
Amino acid metabolism is more complicated than lipid and carbs because
amino acids contain nitrogen
nitrogens jobs
used to make new proteins, broken down for energy, make nucleic acids, neurotransmitters and any nitrogen-containing substances in our bodies
nitrogen intake = nitrogen output
nitrogen balance, total body protein does not change
Nitrogen intake < Nitrogen output
Negative nitrogen balance, total body protein decreases
Nitrogen intake > Nitrogen output
positive nitrogen balance, total body protein increases
amino acid transporters
have specificity for similar charged for neutral aa’s - each aa is usually transported by more than one carrrier
what alongside of dietary proteins will be digested?
Shed intestinal cells and the actual enzymes (make up for a substantial portion off the absorbed aa’s)
Where do amino acids travel to after being taken up?
to the liver to be distributed for protein synthesis
proteins are constantly being ______ and ______, using a number of different enzymes
broken down, re-synthesized
a number of aa’s are ________ aa’s, must be take in the diet
essential
if _____ aa’s are not absorbed from the diet what will be broken down to provide them?
muscle protein
