9. Protein and Amino Acid Metabolism Flashcards Preview

MCM Test 1 > 9. Protein and Amino Acid Metabolism > Flashcards

Flashcards in 9. Protein and Amino Acid Metabolism Deck (27):
1

Where does exopeptidase munch protiens?

What about endopeptidase?

Exo = outside (C or N terminus)

Endo = Inside (Somewhere in the middle; internal peptide bonds)

2

What pathway is used for proteasomal degradation?

Ubiquitin pathway (Protiens are marked by ubiquitin for degradation by a proteosome)

3

Where do the amino groups from protien breakdown go?

To the urea cycle!

4

What happens to the carbon skeletons in protein degradation?

They are used for energy - either storage as glucose / glycogen / fatty acid synthesis or as cellular respiration products (TCA cycle)

5

What is the job of enterokinase?

Extracellular proteolysis

It's found in the small intestine, where it activates trypsin, which activates chymotrypsin.

6

What amino acids are not Glucogenic?

Leucine / Lysine

(Gluconeogenesis is for winners and these AAs are L-osers)

7

What amino acids can be either glucogenic or ketogenic?

Phenylalanine

Isoleucine

Tryptophan

Tyrosine

Threonine

(They have to do TWO jobs? That's the PITTTs!)

8

What important products come from Phenylalanine?

Tyrosine Epinephrine, Thyroid Hormones, Dopamine

 

9

What important coenzyme do transaminases require?

PLP (pyridoxyl-5'-phosphate)

-derived from pyridoxine-

10

What are the clinically relevant transaminases, and what are they used for in the body?

What about a clinical setting?

ALT / AST - both used for Glutamate ⇔ alpha-ketoglutarate reactions

Used as liver funciton markers

11

What kind of amino acids cannot be degraded in the liver?

Where are they degraded?

What specific amino acids are they?

Branch-Chain Amino Acids

Muscle, Kidney, Brain

Valine, Leucine, Isoleucine

12

Other than transaminases, what important amino acid metabolic enzyme requires PLP?
What disease is associated with its deficiency?

cystathionine beta-synthase

It catalyzes homocystine ⇒ Cystathionine, and its deficiency causes homocystinuria.

13

Maple Syrup Urine disease is caused by a buildup of what kind of amino acids?

What is the deficient enzyme?

Branched chain

Branched Chain alpha-ketoacid Dehydrogenase

14

People who pay attention to Phenylketonurics labels might have a deficiency in which enzyme?

Phenylalanine Hydroxylase

15

What amino acid is made into the following?

Epinephrine

Thyroid Hormones

Dopamine

Melanin

Tyrosine

16

What amino acid is made into the following?

Serotonin

Melatonin

Niacin

Tryptophan

17

What amino acid is made into Acetylcholine?

Serine

18

What two amino acids are used to remove ammonia in the brain?

Glutamate / Glutamine

19

What two amino acids are used to remove ammonia in the tissues (not the brain)?

Alanine / Glutamine

(The G bros are the ammonia pros, but the tissues can't afford both - so they just get glutamine and this guy Al from off the street)

20

What aspect of ammonia's toxicity might be most important to Dr. Agbas?

Its ability to cause mitochondrial dysfunction.

It can also permeate membranes to get to the mitochondria.

21

What three amino acids make Creatine?

Methionine

Arginine

Glycine

(MAGazine for storing energy)

22

In regards to ALT

What two Ketoacid/Amino acid complexes are changed between?

ALT

Pyruvate + Glutamate -> alpha-ketoglutarate + Alanine

(ALT is ELITE so it gets Pyruvate, AL- in ALT stands for Alanine. Both use Glutamate / Alpha-KetoGlutarate)

23

In regards to AST

What two Ketoacid / Amino Acid complexes are switched between?

AST

Oxaloacetate + Glutamate Alpha-Ketoglutarate + Aspartate

(AST - A Second-rate Transaminase gets the last product of TCA on one end, and the ASS(partate) end of the amino acid deal on the other)

24

The disease Alkaptonuria (Ochronosis) is caused by a deficiency of what enzyme?

Homogentisate Oxidase

25

Heme can be derived from what Amino Acid?

Glycine

26

What amino acid gives rise to Thyroid Hormones?

27