NFS 3115: Proteins
Terms in this set (66)
What are the 9 essential (indispensable) AA?
TRYPTOPHAN, THREONINE, HISTADINE, LYSINE, leucine, isoleucine, methionine, phenylalanine and valine
PVT TIM HALL
Aliphatic amino acids
Glycine, Alanine, Valine, Leucine, Isoleucine
OH (hydroxyl) containing AA
Serine and threonine
Sulfur containing AA
cysteine and methionine
AA with acidic side groups or their amines
Aspartic acid, Asparagine, Glutamic acid, Glutamine
AA with Aromatic rings
Phenylalanine, Tyrosine, Tryptophan
The only AA with an imino acid group is ______
AA formed Post translationally are ?
cysTINE, hydroxylysine, hydroxyproline and 3-methylhistadine
Arginine & Lysine (contains elision group and alpha group)
4 TRULY essential AA:
lysine, histadine, threonine and tryptophan
TRULY he likes trying things
why are the TRULY essential AA truly essential?
because they do not undergo transamination and therefore even if the precursor was available in the diet, humans would not be able to synthesize them.
Mammals on the test should be replaced with
why are 5 of the essential AA not truly essential?
b/c they can undergo transamination and thus if precursors were in the diet, we could synthesize them.
what are the 5 non-truly essential AA?
methionine, leucine, isoleucine, valine, and phenylalanine.
How are nonessential/dispensible AA synthesized?
1. The precursor molecule is synthesized and then transaminated using glutamate as the source of the amino group
2. OR is synthesized from essential AA via various chemical reactions
what is an alpha amino acid?
AA where the amino group is attached to the first (alpha) carbon. This is the carbon with the R group attached to it.
___of protein in skeletal muscle, ____ in body organs, and the rest mainly in skin and blood
40% of protein in skeletal muscle,
25% in body organs
enzymes that cleave compounds
enzymes that transfer atoms within a molecule
_____ enzymes join compounds
_____ enzymes transfer electrons b/w molecules
_____ enzymes move FG between molecules
roles of proteins include
immune protectors (ex: IgA)
transport (Hg, lipoproteins, albumin, transferrin)
glycoproteins (protein with OGS side chain)
role of protein in edema
protein attracts water. When blood protein is low, there is more protein in intermembrane space, which pulls in water causing swelling. This can be caused by malnutrition and is a symptom of kwashiorkor (protein deficiency)
_______ is achieved through H bonding of carboxyl and amino groups present on the SAME PP chain (due to folding).... results in alpha helix, beta pleated sheets or random coils
______ structure (linear, globular or spherical) affects shape and function
Hg is a good example of _____ structure
quaternary (interaction b/w 2 or more PP chains)
another name for quaternary structure of protein (e.g. hemoglobin)
______ is an amino acid with an α and ε (c5) amino groups
_____ undergoes reversible transamination with several AA's producing AKG or other alpha amino acids
when pH is low proteins _____ H's
accept (on carboxyl end)
when pH is high, proteins ____ H's
donate (from amino end
_____ may be important for gut health
negatively charged AA
+ charged AA
conditionally essential amino acids means....?
they are required at some stages or growth or by some people who cannot synthesize them, either because of genetics or a medical condition.
Ex: PKU cannot consume phenylalanine so tyrosine becomes essential
what are the conditionally essential AA?
arginine, cysteine (from methionine)
glutamine, glycine, proline, tyrosine (phenylalanine)
According to Katagiri and Nakamura
glutamate is produced from
α-ketoglutarate and an _______
α-amino acid (NOT ammonia)
how is glutamine formed?
Glutamine is formed by the addition of an amino group on the epilson carbon of glutamate. This Amino group is lost, when glutamine is used to synthesize asparagine from aspartate, generating glutamate again.
When a NONESSENTIAL amino acid is not available from the diet, it can be made in the body by the process of _______
the carbon skeleton of a protein used for transamination contains all the parts of an AA except for the ______ group
what is transamination
replacing =O with an amine or an vice versa (e.g. adding amine group to glutamate creates glutamine)
glutamate can be used to synthesize what AA?
alanine, asparagine, serine,
when glutamate passes its amine group it becomes ______
AKG + Alpha AA ---> glutamate ---> glutamine
how is AKG formed?
when glutamate losses its amine group.
AKG has no amines
gluta____ has two amine groups
T/F do we consume the precursor molecule?
NO it is not ordinarily part of diet without the amino group. Precursor is in our diet but it is not free (without its amino group)
what is the amount of protein provided by endogenous proteins?
Desquamated mucosal cells = 50g per day
Digestive enzymes & glycoproteins = 17g per day
is synthesized by the transfer of a ammonia group from glutamate to oxaloacetate.
aspartate and alanine can be made from the addition of an amino group to oxaloacetate and pyruvate, respectively
the amino group from glutamate can be transferred to other α-ketoacids by transamination reactions
Three α-ketoacids ___,____,_____can be converted into amino acids in one step through the addition of an amino group.
α-ketoglutarate, oxaloacetate, and pyruvate
1. glutamate + pyruvate =
2. glutamate + Oxaloacetate =
1. alanine + AKG
2. aspartate + AKG
carbosxypeptidases are secreted by ____
aminopeptidases are secreted by ____
intestinal mucosal cells
______ hydrolyze dipeptides
pepsinogen --> pepsin is activated by
gastric juice and activated pepsin in stomach
In response to partially digested proteins entering SI, the hormones secretin and CCK are released which causes ______ to be released.
Enteropeptidase in the SI activates ______ a precursor of _____
trypsinogen, precursor of trypsin
once trypsin is activated by enteropeptidases in the SI, it activates many other proteases such as:
chymotrypsinogen --> chymotrypsin
proelastase --> elastase
procarboxypeptidase ---> carboxypeptidase
proaminopeptidase --> aminopeptidase
What are then end products of exo/endopeptidases? How are they absorbed
1. Free AA- absorbed across intestinal cell via sodium DEPENDENT active transport
2. di, tri, and oligopeptidases - di and tri are broken down to free AA on brush border of SI and transported to hepatic portal vein. Larger peptides may be absorbed whole through or between epithelial cells. These 3 types of AA compete for absorption and uptake by their specific transporters!
explain how AA are broken down in SI
1. (CCK/secretin) = Enteropeptidase
2. Enteropeptidase --> trypsinogen
3. Trypsinogen --> carboxypeptidases, aminopeptidase
4. Free AA are absorbed by Na+ dependent, active transport
5. di/tri peptidases are broken down by brush border peptidases and are absorbed via PEPT1
Aminopeptidases, dipeptdylaminopeptidases, tripeptidases
brush border peptidases
promote protein synthesis
insulin and growth hormone
urea cycle occurs in the _____, the urea is sent where?
sent to kidney and excreted in urine
what aa is produced in urea cycle
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