Exam 1 biochem Flashcards Preview

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Flashcards in Exam 1 biochem Deck (19):
1

Synthesis of heme starters

glycine and succinyl-CoA (initially)

2

Heme pocket properties

hypdrophobic residues
mouth of pocket is polar residues
Fe2+ covalently linked to His F8

3

Highly conserved residues of hemoglobin

prox His (F8)
distal His (E7)
glycine (B6), allows B and E helices approximation

4

Fetal hemoglobin

has gamma instead of beta subunits
replaced starting 3 months prior to birth

5

Hemoglobin gene locations

chromosome 11 for epislon, gamma, delta, beta
chromosome 16 for zeta and alpha

6

Oxygen binding to hemoglobin

T state is low affinity
R state high affinity
T to R shift axis by 15 degrees
heme flattens out in R state

7

Bohr effect of oxygen binding

decreased pH increases oxygen release
allows more release to metabolically active tissues
due to stabilization of T state with protonation (mostly His and Val residues)

8

CO2 binding to hemoglobin

forms salt bridges
stabilizes T state
increased oxygen release

9

Bisphosphoglycerate and hemoglobin

BPG increases oxygen release
stabilizes T state in center of Hb
oxygen binding expels BPG in center

10

Fetal and maternal Hb affinities

Fetal Hb has lower affinity for BPG
increases oxygen binding over maternal Hb
due to Serine instead of His on 143 beta

11

Hemoglobin S

Glu6Val mutation
sticky patch on S and T states
causes polymerization of Hb's
sickling of cells

12

Hemoglobin C

mild hemolytic anemia
Glu(beta6)Lys mutation

13

Hemoglobin M

promotes metHb formation
cyanosis

14

Sickle Cell disease

splenic sequestration
RBC depletion/anemia
pain episodes
kidney failure

15

Acute sickle dactylitis

aka Hand/foot syndrome
swelling of hands/feet
sx in young children
tx with fluids/pain meds

16

Thalaseemias types and mutations

alpha-deletion
beta-point mutations

17

Alpha thalassemia

gamma 4- Hb Bart's (fetus)
beta 4- Hb H (adult)
tetramer formation

18

Polycythemia

decreased oxygen release
causes increased RBC production

19

Glycosylated Hb

Glc binds Hb in high serum conc
good for monitoring diabetics (HbA1c)