Set 5 Amino Acids

Front 1

the joining of two peptides is a _______ reaction

Back 1

Dehydration/condensation

Front 2

Which AAs are aromatic?

Back 2

Tryptophan, tyrosine and Phenylalanine

Front 3

Which AAs are basic?

Back 3

histidine, Arginine, and lysine

Front 4

Which AAs are acidic?

Back 4

Glutamic Acid, and Aspartic Acid

Front 5

Which AAs are polar?

Back 5

Cysteine, Serine, Threonine, Asparagine, Glutamine

Front 6

Which AAs are non-polar

Back 6

Glycine, Alanine, Valine, Leucine, Isoleucine, methionine, and proline

Front 7

What happens to proteins if you intake an excess of them?

Back 7

They cannot be stored, so they undergo oxidative degradation

Front 8

What happens to your proteins if you are starving,

Back 8

Cellular proteins may be used as a fuel source if no carbohydrates.

Front 9

Can cellular proteins be stored?

Back 9

No, proteins aren't stored in the body. They are used as enzymes and structures, but there is a constant turnover.

Front 10

What is a positive nitrogen balance?

Back 10

Protein Synthesis > protein degradation

Front 11

What is a negative nitrogen balance

Back 11

Protein Synthesis < protein degradation

Front 12

what is a zero nitrogen balance

Back 12

Protein Synthesis = protein degradation

Front 13

what is the equation for nitrogen balance

Back 13

N balance = N consumed (primarily protein) - N excreted (mostly as urea)

Front 14

What is a zymogen?

Back 14

an inactive enzyme precursor

Front 15

What is the first step of degradation when protein enters the stomach

Back 15

Gastrin is released by the gastric mucosa into the bloodstream.

Front 16

What is the role of Gastrin?

Back 16

Gastrin cause parietal cell to secrete HCL, lowering the pH of the stomach to 1-1.5.

Gastrin also causes chief cells to release pepsinogen ( a zymogen), which will autocatalytically cleave itself into pepsin when the pH is low enough.

Front 17

What does pepsin do?

Back 17

Pepsin hydrolyzes the peptide bond at the amino terminus of aromatic amino acids.

Front 18

Low pH in the Duodenum (first compartment of the small intestine) causes S cells to secrete which Hormone into the bloodstream? What does this Hormone do?

Back 18

Secretin. Secretin causes the pancreas to release HCO3-, which raises the pH of the duodenum to around 7.

Front 19

Which hormone is released into the bloodstream by mucosal epithelial cells after they sense AAs in the small intestine? and what does this hormone do?

Back 19

CCK (cholecystokinin). Causes the release of Zymogens into the intestine.

Front 20

Which zymogens get released by CCK?

Back 20

Trypsinogen, chymotripsinogen, and procarboxypeptidases A and B

Front 21

Where organ secretes Trypsinogen, chymotripsinogen, and procarboxypeptidases A and B

Back 21

the pancreas

Front 22

Which enzyme activates tripsinogen into trypsin?

Back 22

enteropeptidase

Front 23

Which enzyme activates Chymotripsinogen, procarboxypeptidases A & B, and proelastase into their activate forms?

Back 23

trypsin.

Front 24

What is the point of creating all of these active enzymes in the Intestine?

Back 24

So peptidase reactions can occur to break down proteins into Di and tri peptides, which can be absorbed in the villi of the small intestine.

Front 25

Can Amino acids travel in the blood by themselves?

Back 25

yes, they are soluble in polar fluids.

Front 26

Explain the path of a protein after it is ingested, and as it moves through the digestive system into the small intestine.

Back 26

A protein is ingested in the mouth. Once the protein reaches the stomach, Gastrin is released by the gastric mucosa. Gastrin induces Parietal cells to secrete HCl, Decreasing the pH of the stomach to 1.5-2. Gastrin also induces Chief Cells to released Pepsinogen, a zymogen of the enzyme pepsin. Under the low pH, pepsinogen autocatalytically cleaves itself into pepsin. Pepsin begins to cleave AAs at the Amino terminus of aromatic AAs residues.

THe Polypeptide chains get moved into the Duodenum of the small intestine, where they are sensed by the mucosal epithelium, causing them to release CCK (cholecystokinin), which induces the pancreas to release a bunch of zymogens into the small intestine (chymotrypsinogen, trypsonigen, procarboxypeptidases A&B). Enteropeptidase in the small intestine converts trypsinogen into trypsin, which can then activate the other zymoges, as well as proelastase-->elastase, so these enzymes can continue to degrade the polypeptides into Di and Tr peptides so they can be absorbed by the intestinal villi.

Front 27

When are AAs catabolized?

Back 27

When more AAs are ingested than are needed for Protein synth,

-When the body is lacking OAA/starving.

-When AAs from protein turnover are not needed for protein synthesis.

Front 28

When AAs are catabolized by the liver, what enzyme is used to remove their amino groups?

Back 28

Aminotransferases (or transaminases)

Front 29

L-AminoAcid+ Alpha-KetoGlutarate ---> _____ + ______. What enzyme catalyzes this reaction?

Back 29

Alpha-Keto Acid + Glutamate. Aminotransferase.

Front 30

What is the role of Glutamate in AA catabolism.

Back 30

Glutamate collects Amino Groups of many different AAs, and it is used as an Amino donor for biosynthesis pathways, and it is the lead molecule for excretion via the Urea cycle.

Front 31

Are aminotransferase reactions reversible, and what are the implications of this?

Back 31

Yes, they are reversible (have a delta G nought of about 0 kJ). This means that if Reactants, or products build up, the reaction will shift towards equilibrium. Neither products or reactants will be able to build up in appreciable quantities relative to each other.

Front 32

Which prosthetic group is used by All aminotransferases?

Back 32

PLP (pyridoxal Phosphate)

Front 33

What are prosthetic Groups?

Back 33

Prosthetics groups are metal Ions, or coenzymes (org. mcs) that are covalently, or tightly bound to an enzyme's active site that are not part of a enzymes primary structure.

Front 34

which Vitamin is also known as Pyridoxine?

Back 34

Vitamin B6

Front 35

What is Pyridoxine derived from, and where do obtain this nutrient?

Back 35

Vitamin B6. Leafy greens.

Front 36

how does PLP stay bound to an animotransferase?

Back 36

PLP is linked to the epsilon amino group of a lysine residue in the Aminotransferases active site via a SHIFF BASE REACTION

Front 37

What is a shiff base reaction?

Back 37

it is a primary amine and an aldehyde. (the nitrogen is in the place of a where the Oxygen would be in a typical Aldehyde. the "carbonyl C" is connected to the N via a double bond, and the Nitrogen has a single H attached, and another chain.

Front 38

compare an 'external" aldimine to an "internal" aldimine.

Back 38

Internal aldimines have Pyridoxal Phosphate bound to the aminotransferase's lysine residue via a shiff base reaction.

External Aldimines have Pyridoxal phosphate bound to an AA not part of the Aminotransferase enzyme.

Front 39

What type of stereochem do Amino acids in the body have?

Back 39

L

Front 40

What constitutes the "ping" portion of a ping pong reaction?

Back 40

PLP is bound to the aminotrasnferase e via a shiff base reaction to the E-Amino group of a lysine residue.

-An amino Acid comes in, and displaces the lysine residue, and a shiff base forms between the External AminoAcid and PLP

THe Alpha-keto Acid is released, and the Amino group remains bound to PMP (newly formed).

Front 41

What does PMP stand for?

Back 41

Pyridoxamine Phosphate

Front 42

Explain the "pong " portion of the ping pong reaction

Back 42

A different Alpha Keto Acid Will enter, reacting with the Amino group on PMP, forming a shiff base reaction with (now) PLP. The L-Amino acid is then displaced by the lysine residue on Aminotransferase, and the holoenzyme is restored.

Front 43

when does PLP turn into PMP

Back 43

When there is only an amino group attached. If an AA is attached, it is always PLP.

Front 44

What is the Alpha Keto Acid Produced from the reaction of Alanine + Alpha-KetoGlutarate --> Glutamate + __________

What enzyme catalyzes this reaction?

Back 44

Pyruvate

Alanine Aminotransferase.

Front 45

Which Alpha Keto Acid is produced from the reaction of

Aspartate + Alpha Ketoglurate ---> Glutamate + __________

Which enzyme catalyzes this reaction?

Back 45

OxaloAcetate (OAA)

Aspartate Aminotransferase.

Front 46

Why are AST/ALT (Aspartate Aminotransferase/Alanine aminotransferase) usually found on blood test.

Back 46

They are usually indicators for Tissue damage, such as liver damage, and or heart damage. Often used to diagnose Heart attacks, and maybe alcoholism (just a though, not sure about diagnosing drunks)

Front 47

How can aspartate be synthesized within the cell?

Back 47

React glutamate with oxaloacetate (catalyzed by aspartate aminotransferase) to produce Alpha- KG and Aspartate

Front 48

How can alanine be produced within the cell?

Back 48

react with Pyruvate with glutamate (Alanine aminotransferase) to produce alanine and alpha-KG