Amino acids

Question 1

What element of the amino acid defines its structure?

Answer 1

R group

Question 2

What is a peptide bond

Answer 2

COO- and H3N, amino acid sequence defines the primary structure of the protein

Question 3

What are the two means though which the body is able to restore protein concentrations?

Answer 3

• digestion and absorption

- though protein degradation

Question 4

What are the two pathways for protein degradation?

Answer 4

1. Ubiquitin

2. Lysosomal degradation of enzymes

Question 5

How big is the amino acid pool within a human?

Answer 5

amino acid pool is 500 grams

Question 6

How does the ubiquitin pathway work, is it regulated and is it ATP dependant?

Answer 6

• ATP dependant pathway

- degradation of ubiquinated proteins in proteosomes

Question 7

Explain how the lysosomal degradation of enzyme occurs, the degree of regulation and whether it is ATP dependant:

Answer 7

• Mostly independant of ATP
• internalised to lysosomes
• regulated

Question 8

What must we do to an amino acid before it is useful?

Answer 8

need to remove amino- N before the carbon skeleton is useful for energy or gluconeogenesis

Question 9

What are the entry points for carbon from amino acids?

Answer 9

• amino acids that increase TCA cycle intermediates
• amino acids that increase both TCA intermediates and acetyl CoA
• amino acids that just increase acetyl CoA

Question 10

What are the two main enzymatic players that are involved transamination and direct deamination?

Answer 10

• transamination- occurs in all tissues, but mainly in the liver
• direct deamination- liver and the liver and kidney

Question 11

What are the three transaminases that are in all tissues but mainly in the liver?

Answer 11

alanine transaminase
aspartate transaminase
glutamate transaminase

Question 12

What are the enzymes that are involved in direct deamination?

Answer 12

glutamate dehydrogenase (liver)
glutaminase (liver and kidney)

Question 13

How do we get rid of ammonia, what is the name and the molecule and where is it transported to?

Answer 13

needs to be converted into urea, mad in the liver, transported in the blood and excreted through the kidneys

Question 14

What is the energy cost of producing a molecule of urea?

Answer 14

4 ATP

Question 15

Where does the nitrogen come from urea

Answer 15

one comes from oxidative de-amination (glutamate) whereas the other typically comes from transamination from aspartate

Question 16

How is the urea cycle regulated?

Answer 16

enzyme induced by 20 fold by high protein and starvation

Question 17

Where is urea cycle nitrogen sourced from?

Answer 17

glutamate
asparatate
glutamine

Question 18

What is used to stimulate carbomoyl phosphate synthtase one allosterically?

Answer 18

N-acetyl glutamate

Question 19

What is the name to the enzyme that is used to convert glutamate to glutamine and is ATP required or used?

Answer 19

ATP is used, glutamine synthetase

Question 20

What is the name of the enzyme that is used to convert glutamine to glutamate?

Answer 20

glutaminase

Question 21

What is another use for glutamine?

Answer 21

transports amino N to the kidney for the nitrogen to be disposed of directly

Question 22

What is the precursor of glycine and the enzyme that is involved?

Answer 22

• serine is the precursors

- the enzyme that is involved is serine hyroxbmethyltransferase

Question 23

What are the two main reasons for the high protein requirement of cats?

Answer 23

1. Inability of enzymes involved in amino acid catabolism to adapt to changes in dietary protein intake
2. Decreased capacity to regulate protein regulation

Question 24

Do bos inducus cattle have low or high levels of the calpastatin protein?

Answer 24

high levels of calpastatin protein