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Biochemistry > Heme Metabolism > Flashcards

Heme Metabolism Flashcards

1
Q

What is Delta-aminolevulinate formed from

A

Glycine and Succinyl CoA

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2
Q

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

A

Delta aminolevulinate synthase (delta ALA); B6

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3
Q

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

A

8 molecules of each

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4
Q

What inhibits Delta aminolevulinate synthetase

A

Lead

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5
Q

What enzyme is required to insert Fe2+ into protoporphyrin IX

A

ferrochelatase

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6
Q

What is porphyria

A

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

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7
Q

1 delta-ALA + 1 Delta-ALA =

A

porphobilinogen

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8
Q

What are some common uses of Heme

A

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

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9
Q

What regulates delta ALA synthetase

A

End product inhibition from heme

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10
Q

What inhibits ferrochelatase

A

Lead

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11
Q

What is heme degraded into

A

Biliverdin and then Bilirubin

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12
Q

What transports Bilirubin in the blood

A

albumin

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13
Q

What do bacteria do to bilirubin

A

Convert it to stercobilins and urobiliogen

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14
Q

What is hemopexin

A

Scavenges free heme in the blood

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15
Q

What is haptoglobulin

A

Scavenges free hemoglobin in the blood

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16
Q

What is transferrin

A

protein that carries 2, Fe3+ in circulation

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17
Q

What is ferritin

A

liver protein that stores many Fe3+

18
Q

What is hemosiderin

A

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

19
Q

What is pre hepatic jaundice

A

conditions that cause excessive RBC destruction, overwhelming heme degradation capacity

20
Q

What is hepatic jaundice

A

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

21
Q

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

A

Prevents the iron in the blood from catalyzing fenton reactions

22
Q

What is the difference between bilirubin and biliverdin

A

Bilirubin is the reduced form, biliverdin the oxidized form

23
Q

What does Heme oxygenase do

A

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

24
Q

What is the role of CO

A

Potent vasodilator and may also be a signaling molecule

25
Q

What are components of the reticuloendothelial system (RES)

A

Splenic (and kupffer) cells that are “resident Macrophages”

26
Q

Why are many porphyrias photosensitive

A

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

27
Q

Why does the skin look yellow in jaundice (icterus)

A

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

28
Q

Why does light therapy help mildly jaundiced babies

A

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

29
Q

What is a key sign of post hepatic jaundice

A

Chalky white stool

30
Q

What is the daily dietary intake of iron

A

15 mg

31
Q

What is the daily dietary intake of copper

A

1.3 mg

32
Q

What is the function of ferrooxidase

A

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

33
Q

How does iron leave the body

A

Through sweat, bile, excretion, dead cells

34
Q

How does copper leave the body

A

Primarily lost in bile

35
Q

What is ceruloplasmin

A

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

36
Q

How does Vit C affect iron absorption

A

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

37
Q

What are some roles of Copper

A

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

38
Q

What are some roles of Vit C

A

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

39
Q

What cells depend on Copper for tyrosinase

A

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

40
Q

What is required to convert tyrosine to DOPA

A

a methyl group and copper (sometimes)

41
Q

What is required to convert DOPA to dopamine

A

B6 and a CO2 leaves

42
Q

What is required to convert dopamine to norepinephrine

A

O2, Cu2+, Vit C

Biochemistry (4 decks)

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