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BMS I > Heme Biosynthesis Flip Class > Flashcards

Heme Biosynthesis Flip Class Flashcards

1
Q

Structure of heme

A

4 pyroles (pent with N at top and two double bonds)

Either methyl, vinyl, or propionate
-arrangement of side chains is important for activity

Fe+2

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2
Q

Heme aka

A

Protophyrin IX

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3
Q

p450 class enzymes

A

Synthesized by heme

In liver-liver detox, synthesis of vit D, cholesterol syn, synthesis of bile and bile acids

Decrease in these enzymes leads to heme biosyn

Incrased sun after 4M

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4
Q

Porphyrin precursors

A

ALA and PBG

Water soluble and are excreted and measured in urine

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5
Q

Porphyrinogens

A

Larger-aqueous stability varies based on number of carboxylic acid (acidic) side chains

Biologiacally active

Reduced

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6
Q

Porphyrins

A

Detected and measured in a labs

Oxidized-creates conjugation system that allows molecules to abosrt visible light
-Produces reactive species in tissue

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7
Q

Heme biosynthesis pathway

8 steps

A 
Succinyl CoA+glycine
-delta aminolevunlinic acid synthase
2 Delta aminovulnic acids
-delta aminovulinic acid dehhydratase
4 Porphobilinogen
-Porphobilinogen deaminase
Hyroxymethbilane
-UROIII Cosynthase
UROIII
-URO Decarboxlyase
COPROIII
-Copro Oxidase (all phyrinogen above)
Protophyrinogen IX
-Proto oxidase
Protophyrin 9
-Ferrochelatase and Fe2+
Heme
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8
Q

what parts of heme biosyn are in mito

A

succinyal coa and glycine to ALA
and
Copro III to Heme

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9
Q

ALAS=

A

Vit B6

Pyridoxal phosphate

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10
Q

Committed step?

A

ALAS

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11
Q

Inhibited by Fe

A

ALAS II

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12
Q

Inhibited by Pb

A

ALAD, Ferro (less sensitive), Pyrimidine 5’ nucleotides

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13
Q

Where is heme syn?

A 
Bone marrow (85%)
Liver
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14
Q

What stops heme syn

A

RBC mature

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15
Q

1st step

A

Sucinyal CoA and glycine to delta Aminivulinate

b6

ALAS1 or housekeeping in liver
ALAS2 (inhabit by Fe)

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16
Q

1st step inhib

difference with ALASII

A

hematin, hemin heme,(allosteric inhib)

Heme (inhibits alas to cyto)

Heme, insulin , glucose-repress trx of ALAS

Has IRE-translation blocked by Pb

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17
Q

2nd step

A

2 molecules ALA to PBG by ALAD

ALAD contains Zn

1st precursor pyrole

Inhibited by Pb

18
Q

1st step activation

A

4M

Liver-metabolize p450 stuff

induce sun of p450-need heme

decrease concentration of heme in cells

19
Q

4m

A

meds, maladies, bleeding, malnutrition

increase p450 sun

20
Q

3rd step

A

4PBG+PBGD=HMB

21
Q

4th step

A

HMB+UROIIIS=UROIII+UROIIID=COPROI
or
high conc
HMB spont to UROI spont to COPROI

22
Q

URO III, COPROIII, Protophyrinogen IX

excretion

A

urine, urine and blie, blie

23
Q

Siderblastic anemia

A

ring siderblasts in bone marrow (excessive Fe accumulation)

Impaired heme biosyn

Microcytic and hypochromic

Mito metabolism problems

Nucleated RBC

24
Q

hereditary sidero anemia

A

X-linked-erythroid spec=ALAS2

mtDNA mistake

25
Q

Aquired

A

Myedisplasia-mtDNA pt muts

Drugs-Isoniazid/ethanol

Toxins-lead

Nutritional-pyrixidoxine defeciency

26
Q

Trx Pb poisoning

A

chelators

27
Q

Pb poisioning presentation

A

lethary, ab discomfort,

anemia, gingival and long bone pb line, headache

convulsions, coma, renal failure

28
Q

Diagnosis of Pb poisoning

A

ALA in urine
ZPP in blood (goes into protophyrin 9 instead of Fe)
Basophilic stippling in peripheral smear

29
Q

Acute porphyria vs nonacute

A

acute-ALA/PBG up, decrease in heme-neuropsych signs and symtoms

Nonacute-accumulation of porphyrinogens in skin and tissue, spontaneous oxidation of porhyringens to porphyrins, photosenstivity

30
Q

acute and non acute porphyria sims

A

mostly auto dom

both have genetic and non genetic factors

(some are auto rec tho)

31
Q

AIP

A

PBGD defieciency

32
Q

Symptoms of AIP

A

Accumulation of ALA and PBG
-neurotoxic levels

NO SKIN LESIONS

Gi disorder, psych disorders,

all at risk for liver cancer

Attack of AIP after 4M

2nd most common

33
Q

PBG in urine

A

Brown/Red

34
Q

AIP trx

A

Avoid 4M, glucose loading, admin hemin/hematin, stop p450 syn

DECREASE ALA SYN

35
Q

PTC

A

UROD Problem

Acquired or autu dominant (familial PCT)

36
Q

Factors affect PTC onset

and symptoms

A

4th/5th decade onset

alc, fe overload, sunligh, HIV/HEP C/B

bullae, hypertrichosis, heliotrope, sclerodermoid plaque, dark urine, milia

37
Q

milia, bullae, hypertrichosis, helitrope

A

milic-small white bumps in skin

hypertrichosis-har growing in weird splot

bullate-fluid filled blister (large)

heliprope-purple-red face skin

38
Q

What causes bad things in PTC

A

ring intermediates getting hit by sunlight and become reactive O2 species

39
Q

PTC diagnosis

A

Uro to copro 3:1 instead or 5:1

more 8-7 carboxyl porphyrin fractions

UROD in blood analysis

40
Q

Trx for PTC

A

No env exosures

Sunscreen

Fe Chelator

Bleeding (reduces Fe stores and heme syn up)

41
Q

EPP

A

Autodom

Ferrochelatase mutation

Early childhood presentation

SEVERE PHOTOSENSTIVITY

Chornic liver diease

BMS I (30 decks)

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