Amino Acid Degradation

Question 1

What are the steps of metabolic flow of amino acid nitrogen

Answer 1

transamination, deamination, and urea formation

Question 2

Whats the purpose of transamination?

Answer 2

transfer of amino group of amino acid to an alpha-keto acid

Question 3

What are the enzymes used in transamination

Answer 3

aminotransferases (ALT and AST)

Question 4

What is the cofactor needed in transamination?

Answer 4

pyridoxal phosphate (B6 derivative) which is also required in glycogen breakdown

Question 5

What is the purpose of oxidative deamination?

Answer 5

reversible reaction determined by levels of glutamate, alpha-ketoglutarte, ammonia

Question 6

Enzymes used in deamination?

Answer 6

glutamate dehydrogenase

Question 7

What are the cofactors in deamination?

Answer 7

NAD+ or NADP

Question 8

What is urea

Answer 8

low toxicity, water-soluble metabolite; enters blood, excreted in urine

Question 9

Where is the location of the urea cycle?

Answer 9

liver

Question 10

Where is the cellular location of urea cycle?

Answer 10

First two reactions occur in mitochondrial matrix; final reaction occurs in the cytosol.

Question 11

How many ATP are needed in the conversion to urea?

Answer 11

3

Question 12

What are some sources of urea nitrogen?

Answer 12

Brain, muscles, Asparagine, glutamine, glutamate, serine, gut

Question 13

How is the urea cycle linked to krebs cycle?

Answer 13

linking element is fumarate

Question 14

Where do the nitrogens in urea come from?

Answer 14

carbarnoyl phosphate and aspertate

Question 15

What is needed to go from L-aspartate to argininosuccinate in the urea cycle?

Answer 15

ATP and the enzyme is argininosuccinate synthase

Question 16

Where is the urea cycle is fumarate released and where does it go?

Answer 16

Released from the reaction argininosuccinate to L-arginine. Fumarate goes to the krebs cycle.