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Flashcards in hemoglobin Deck (13):
1

MCH

mean hemoglobin per cell in picograms

2

most hemoglobin synthesis occurs during this stage:

polychromatophillic

3

hb concentration

15 g /dL blood

4

Heme synthesis

condensation of glycine and succinyl CoA. occurs only in presence cofactor pyridoxal phosphate and the enzyme 5-aminolevulinate synthase (ALAS). Rate limiting step only occurs in presence of iron. This step occurs in mictochondria, exits to cyoplasm to form Coproporphyrinogen then reenters mitochondria to form protoporyhyrin IX.

5

ferrochelatase

chelates iron with protoporyphyrin Ix

6

zeta chain

fetal alpha equivalant. very early embryonic development.

7

short arm chromosome 16

zeta and alpha location. two alpha loci.

8

Beta like genes

located in order of activation on chromosome 11. E, Gamma, D and B.

9

non alpha affinity for alpha

Beta > gamma > delta

10

AHSP alpha hemoglobin stabilizing protein

AHSP binds free a@chains and stabilizes their structure, increasing their affinity for b@chains. This accelerates the formation of hemoglobin tetramers.

McKenzie, Shirlyn B.; Williams, Lynne. Clinical Laboratory Hematology (3rd Edition) (Pearson Clinical Laboratory Science Series) (Page 82). Prentice Hall. Kindle Edition.

11

Heme binding position

6 electrons in iron. four bind heme, 1 binds proimal histidine F8 other is for oxygen. Located between proximal and distal E8 histidine.

12

Regulation of hemoglobin synthesis

activity concnetration of ALAS2,
Activity of porphobilinogen deaminase (PBGD) • Concentration of iron • Regulation of globin chain synthesis

13

Heme role in regulation

inhibits mitochondrial import of ALAS 2, inhibits iron uptake via transferrin. Decreased iron inhibits ALAS2 synthesis.