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Biochemistry > Heme > Flashcards

Flashcards in Heme Deck (16)
1

Structure of Porphyrins

4 5-membered rings w/ Ns facing inwards

2

Beginning of Heme Synthesis

Gly and succinyl CoA joined by ALAS (ALA synthase) 1 and 2 to create ALA

3

Difference b/w Anemia and Porphyrias

Anemia is making heme fine but it has short life
Polyphoria is blockage of heme synthesis pathway, and heme is an inhibitor of ALAS so start synthesizing shitton of intermediates that buildup wherever the blockage is

4

Heme Degradation 1st Stop (3)

Macrophage consumes
Oxidized to biliverdin
Reduced to bilirubin for albumin-mediated transport through blood to liver

5

Bilirubin glucuronyl-transferase

In liver uses 2 UDP-glucuronic acid to convert bilirubin to bilirubin diglucuronide into bile

6

Bilirubin in Intestine (4)

Glucuronic acid removed by bacteria to convert to urobilinogen
Urobilinogen either recycled back to liver, sent to kidneys where it becomes yellow urobilin, or oxidized by gut bacteria to brown stercobilin

7

Hemolytic Jaundice

Something like G6P Dehydrogenase deficiency causes rapid release of heme and liver can't process fast enough, causing backup of bilirubin into blood

8

Neonatal Jaundice (& cure)

Newborns don't express bilirubin glucuronyl transferase initially, but premies don't even have stuff to start. UV light treatment can actually cure

9

Catecholamine Synthesis (6)

Tyrosine hydroxylase (dependent on Tetrahydrobiopterin [BH4]) converts tyr to DOPA -> DA -> NOR -> EPI

10

4 Enzymes that Use BH4

Phenylalanine, tyrosine, and tryptophan hydroxylases
Nitric Oxide Synthase

11

Histamine Synthesis

Histidine decarbox'd

12

5-HT Production (2)

Trp hydroxylase uses BH4 to convert to intermediate, then decarbox'd to 5-HT

13

2 Starting Components for Creatine

Arg and Gly

14

Creatine function

Converted to creatine P for quick reserve to regenerate ATP in muscle

15

Creatine Structure

Acetoguanidino group

16

Creatinine

Intermediate b/w creatine and creatine P used to measure kidney function