25: Porphyrin Metabolism - Schmidt Flashcards Preview

CS2 Exam II > 25: Porphyrin Metabolism - Schmidt > Flashcards

Flashcards in 25: Porphyrin Metabolism - Schmidt Deck (31):
1

look at slide 3 layout

draw out the pathway without all the chemical structures

2

synthesize ALA from succinyl-CoA and glycine

aminoleveulinic acid synthase

3

2 molecules of ALA are joined to form

porphobilinogen PBG

done via PGB synthase aka ALA dehydratase

4

four molecules of PBg join to form

uroporphyrinogen

modifications of the side chains generate coporphyrinogen and protoporphyrinogen

5

heme synthesis starts in

mitochondria

6

inserts a Fe2+ into the molecule to yield heme

ferrochelatase

7

low heme concentration activates _____

ALA synthase

(neg feedback loop)

8

induction of p450 enzymes _____ heme synthesis

induces

9

disorder that causes light sensitivity

PCT

observe scarring and blisters on skin

can't go past uroporphyrinogen in pathways and it builds up

10

protoporphyrinogen IX and FE2+ =

heme

via ferrochelatase

(in mitochondira)

11

lead poisoning works where in heme synthesis (2)

block PBG synthase and ferrochelatase

causes symptoms similar to porphyrias

12

AIP is a problem where in heme synthesis?

blocks PBG deaminase

ALA and PBG accumulat in the circulation and in the urine giving the urine a dark red color

causes confusion and sharp abdominal pain

13

PCT is problem where in heme synthesis?

blocks UPG III decarboxylase (no coporphyrinogen III)

14

dark red urine?

AIP acute intermittent porphyria during a porphyria attack

triggered by alcohol disorders or infection

15

UV light fluorescent pink urine ?

PCT

16

see slide 12 and 13 for bilirubin formation pathway

draw it out in notes

17

heme --> bilverdin

via heme oxygenase

18

bilverdin ---> bilirubin

via bilverdin reductase

19

bilirubin ---> bilirubin diglucuronide

conjugation in liver by UGT

20

direct/ conjugated bilirubin =

bilirubin diglucuronide

21

indirect/unconjugate bilirubin =

bilirubin

is not water soluble

22

what should be in urine?

urobilin

23

newborn jaundice

prehaptic jaundice

24

normal urine and feces, but unconjugated bilirubin accumulating in other tissues including brain

prehapatic jaundice

25

pale urine and feces, unconjugated bilirubin accumulates in other tissues including the brain

hepatic jaundice

could be caused by acetaminophen poisoning, hepatitis

26

orange urine, pale feces, conjugated AND unconjugated bilirubin accumulation in other tissues including brain

post-hepatic jaundice

could be caused by gallstones, cancer, cirrhosis of gall duct

27

conjugated bilirubin in system -->

problem with gall duct

28

bilirubin slightly elevated

no bilirubin in urine

reticulocyte count up

hemoglobin low

hemolytic, prehepatic jaundice

29

elevated bilirubin

bilirubin in urine

ALT and AST up

hepatic jaundice

30

bilirubin in urine is indicative of...

cholestasis

31

bilirubin highly elevated

bilirubin in urine

alkaline phosphatase up

cholestatic, post-hepatic jaundice

this one could be rather abrupt