Heme Metabolism Flashcards

1
Q

What is heme important for

A

Major part of hemoglobin, also myoglobin, cytochromes, CYP450, peroxidases and NO synthesis

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2
Q

What is porforin

A

Heme without iron

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3
Q

What are prophyrias

A

Inherited defects in heme synthesis

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4
Q

Intermediates in heme synthesis

A

Pyrole a 4 carbon ring with a Nitrogen
Bilirubin (multiple pyrole’s together)
Porphyrin - bilirubin in a ring
Heme - porphyrin with fe in the middle

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5
Q

How do we make heme

A

Glycine and succinyl coa combine to form g-aminolevulinic acid (ALA) with the help of ALA synthase which then is changed to porphobilinogen with the help of ALA dehydrogenase and then that goes to protoporphyrin and then heme

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6
Q

Regulation of heme synthesis

A

ALAS is inhibited by end products (heme) - end product feedback inhibition
ALAD is Zn dependent

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7
Q

Signs of porphyria

A

Skin rash, photosensitive, abdomen pain, neuropsych symptoms, dark urine

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8
Q

Types of porphyria

A

Erythropoietic

Hepatic (acute or chronic)

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9
Q

What precipitates acute hepatic porphyria

A

Drugs (barbiturates, Etoh)

Stressors

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10
Q

Heme degradation

A

Heme is degraded to biliverdin them to bilirubin (which can cause jaundice)

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