Biochem 36: Urea Cycle

Question 1

Major process for removing nitrogen from amino acid

Answer 1

Transamination

Question 2

In most reactions amino acid is transferred to

Answer 2

α-ketogluterate to make glutamate

Question 3

Glutamate loses nitrogen to become _____ via _______ (enzyme)

Answer 3

α-ketogluterate via glutamate dehydrogenase

Ammonia as product

Question 4

Vitamin B6 deficiency symptoms

Answer 4

Dermatitis, hypochromic anemia, weakness, seizures

Question 5

Vitamine B6 aka

Answer 5

Pyridoxamine

Question 6

Pyridoxal phosphate aka

function?

Answer 6

Active form of vitamin B6

takes amino from glutamate and adds it to α-keto acids

Question 7

Major carriers of nitrogen in blood

Answer 7

Alanine and glutamate

Question 8

Urea nitrogen comes from

Answer 8

alanine

Question 9

OTC deficiency leads to

Answer 9

accumulation of carbamoyl phosphate bc it cant enter the urea cycle

floods the prymidine pathway *no ill effects from this *

elevated blood ammonia causes mental impairment

Question 10

What is cleaved to produce urea

via what enzyme

other product?

Answer 10

Arginine

arginase

ornithine

Question 11

Urea during fasting

Answer 11

Initial spike, levels off once ketolysis begins

Question 12

CPSI function

Answer 12

Combines phosphate, HCO3 and ammonia to make carbamoyl phosphate

Question 13

arginosynthase function

Answer 13

adds aspartate to citrulline to make arginosuccinate

Question 14

arginosuccinate lyase function

Answer 14

removes fumarate from arginosuccinate to make arginine