Heme Metabolism

Question 1

What is Delta-aminolevulinate formed from

Answer 1

Glycine and Succinyl CoA

Question 2

What is the enzyme and cofactor needed to make Delta-aminolevulinate

Answer 2

Delta aminolevulinate synthase (delta ALA); B6

Question 3

How much Glycine and Succinyl CoA is needed to make 1 heme molecule

Answer 3

8 molecules of each

Question 4

What inhibits Delta aminolevulinate synthetase

Answer 4

Lead

Question 5

What enzyme is required to insert Fe2+ into protoporphyrin IX

Answer 5

ferrochelatase

Question 6

What is porphyria

Answer 6

Resulting condition from defect in any one of the enzymes for forming heme

Question 7

1 delta-ALA + 1 Delta-ALA =

Answer 7

porphobilinogen

Question 8

What are some common uses of Heme

Answer 8

Cytochrome, COX, NOS, NADPH oxidase, Peroxidases, Myoglobin, catalase

Question 9

What regulates delta ALA synthetase

Answer 9

End product inhibition from heme

Question 10

What inhibits ferrochelatase

Answer 10

Lead

Question 11

What is heme degraded into

Answer 11

Biliverdin and then Bilirubin

Question 12

What transports Bilirubin in the blood

Answer 12

albumin

Question 13

What do bacteria do to bilirubin

Answer 13

Convert it to stercobilins and urobiliogen

Question 14

What is hemopexin

Answer 14

Scavenges free heme in the blood

Question 15

What is haptoglobulin

Answer 15

Scavenges free hemoglobin in the blood

Question 16

What is transferrin

Answer 16

protein that carries 2, Fe3+ in circulation

Question 17

What is ferritin

Answer 17

liver protein that stores many Fe3+

Question 18

What is hemosiderin

Answer 18

granule of protein, polysaccharide, and Fe3+ formed when iron uptake is high

Question 19

What is pre hepatic jaundice

Answer 19

conditions that cause excessive RBC destruction, overwhelming heme degradation capacity

Question 20

What is hepatic jaundice

Answer 20

Liver condition interferes with bilirubin uptake or conjugation enzyme “bilirubin glucuronyl transferase”

Question 21

Why is it important to have iron binding and heme binding proteins

Answer 21

Prevents the iron in the blood from catalyzing fenton reactions

Question 22

What is the difference between bilirubin and biliverdin

Answer 22

Bilirubin is the reduced form, biliverdin the oxidized form

Question 23

What does Heme oxygenase do

Answer 23

Breaks the alpha bridge in heme to extract Fe2+ and produce CO (carbon monoxide)

Question 24

What is the role of CO

Answer 24

Potent vasodilator and may also be a signaling molecule

Question 25

What are components of the reticuloendothelial system (RES)

Answer 25

Splenic (and kupffer) cells that are "resident Macrophages"

Question 26

Why are many porphyrias photosensitive

Answer 26

Because sun increases production of super oxide, which further interrupts enzyme activity

Question 27

Why does the skin look yellow in jaundice (icterus)

Answer 27

Because much bilirubin is not conjugated(made water soluble) so it accumulates in tissue

Question 28

Why does light therapy help mildly jaundiced babies

Answer 28

Because it isomerizes and oxidizes bilirubin, which makes it water soluble

Question 29

What is a key sign of post hepatic jaundice

Answer 29

Chalky white stool

Question 30

What is the daily dietary intake of iron

Answer 30

15 mg

Question 31

What is the daily dietary intake of copper

Answer 31

1.3 mg

Question 32

What is the function of ferrooxidase

Answer 32

Convert Fe2+ to 3+ to prevent Fenton reaction while iron is bound to ferritin

Question 33

How does iron leave the body

Answer 33

Through sweat, bile, excretion, dead cells

Question 34

How does copper leave the body

Answer 34

Primarily lost in bile

Question 35

What is ceruloplasmin

Answer 35

Copper containing peroxidase enzyme that functions as the main way to move copper in the blood

Question 36

How does Vit C affect iron absorption

Answer 36

It increases it by 15% by reducing non-heme iron to Fe2+

Question 37

What are some roles of Copper

Answer 37

Electron transport, catechol synthesis, tyrosinase, SOD, iron metabolism

Question 38

What are some roles of Vit C

Answer 38

improve iron absorption, collagen synthesis, prepare bile salts, catechol synthesis

Question 39

What cells depend on Copper for tyrosinase

Answer 39

Melanocytes do, neurons and adrenal do not because they have a different variation of tyrosinase

Question 40

What is required to convert tyrosine to DOPA

Answer 40

a methyl group and copper (sometimes)

Question 41

What is required to convert DOPA to dopamine

Answer 41

B6 and a CO2 leaves

Question 42

What is required to convert dopamine to norepinephrine

Answer 42

O2, Cu2+, Vit C