B&B Biochemistry

Question 1

Where does ALL nitrogen in molecules come from?

Answer 1

Amino acids

Question 2

Ingredients for purine synthesis:

Answer 2

1. Ribose phosphate (HMP shunt)
2. AAs
3. Carbons (THF or CO2)

Question 3

Steps in purine synthesis:

Answer 3

1. PRPP
2. IMP
3. AMP and GMP

Question 4

______ is often called a single carbon donor

Answer 4

Folate

Question 5

Ribonucleotide reductase

Answer 5

Removes OH group to make “hydroxy”

Question 6

Ribavarin 3 main points:

Answer 6

1. Antiviral
2. Inhibits IMP dehydrogenase
3. Inhibits purine synthesis

Question 7

Mycophenolate

Answer 7

1. Immunosuppressant
2. Inhibits IMP dehydrogenase
3. Specifically in WBCs

Question 8

Free floating purine fates

Answer 8

1. Uric acid

2. Remade into nucleotides (salvage)

Question 9

3 main things about purine salvage

Answer 9

1. HGPRT
2. APRT
3. Chemotherapy drug mercaptopurine

Question 10

6-Mercaptopurine (6MP) 3 main points:

Answer 10

1. Chemotherapy
2. Mimics hypoxanthine/guanine
3. Inhibits multiple steps in de novo synthesis

Question 11

Azathioprine 3

Answer 11

1. Immunosuppressant
2. Used in IBS
3. Functions as 6-MP

Question 12

Xanthine oxidase

Answer 12

Converts hypoxanthine to xanthine and then can go to uric acid for excretion

Question 13

Guanase

Answer 13

Converts guanine to xanthine and then can go to uric acid for excretion

Question 14

APRT

Answer 14

Converts Adenine to Adenosine-MP and then ADA converts it to Inosine

Question 15

Adenosine Deaminase

Answer 15

Converts Adenosine to Inosine; involved in SCID

Question 16

Pathophys of gout

Answer 16

Excess uric acid production from diet or high cell turnover

Question 17

Tx of gout

Answer 17

Allopurinol

Question 18

Lesch-Nyhan Syndrome

Answer 18

XL absence of HGPRT (they don’t want a Hug Party)

Question 19

Where is uric acid excreted?

Answer 19

The kidneys

Question 20

What are phenylalanine and tyrosine key amino acids for synthethis of?

Answer 20

1. DA
2. NE
3. E
4. TH
5. Melanin

Question 21

What are 3 metabolic disorders that involve phenylalanine and tyrosine?

Answer 21

1. PKU
2. Albinism
3. Alkaptonuria

Question 22

BH4 (Tetrahydrobiopterin)

Answer 22

Cofactor for phenylalanine metabolism; need to regenerate it

Question 23

How is tyrosine made?

Answer 23

By phenylalanine hydroxylase activity on phenylalanine

Question 24

PKU pathophys

Answer 24

Defective phenylalanine hydroxylase; phenylketones appear in the urine (musty urine smell); need to avoid phenylalanine and take tyrosine; pale skin, blue eyes (poor melanin synthesis). No apartame.

Question 25

What sex-related hormone might you see elevated in patients with PKU?

Answer 25

Elevated prolactin