Biochemistry Hemoglobin And Myoglobin

Front 1

how many O2 molecules does myoglobin carry

Back 1

1

Front 2

how many O2 does hemoglobin transport

Back 2

4

Front 3

can Hb carry O2 when the iron is in the Fe3+ form?

Back 3

no

then Hb is called 'methemoglobin'

Front 4

whats the basis for cooperative binding of O2 in Hb

Back 4

O2 binds, drags the proximal histidine, causing conformational change

Front 5

what do you call Hb bound to CO

what color is it

Back 5

Carboxyhemoglobin

cherry red

Front 6

why is carboxyhemoglobin toxic?

Back 6

it prevents already-bound O2 from dissociating

Front 7

why does CO bind to Hb much less strongly than to free Hb

Back 7

it only binds to the iron in a strained configuration d/t a distal histidine group, O2 binds at an angle so its not affected

Front 8

does the Tense or Relaxed form have HIGHER affinity for O2 binding

Back 8

Relaaaaxed

Front 9

what does BPG stand for

Back 9

2,3 - Biphosphoglycerate

Front 10

whats BPG do?

Back 10

Negative allosteric effector of O2 binding to Hb

decreases affinity of Hb for O2

Front 11

BPG is synthesized from a precursor in the glycolytic pathway. What are 2 implications of this

Back 11

1. deficiency in hexokinase decreases BPG in a cell, so Hb will bind O2 more tightly
2. deficiency in pyruvate kinase (the last enzyme in the path) means an accumulation of all intermediates, including 1-3 BPG, the precursor of BPG, curve shifts to right, weaker binding of O2

Front 12

does Mb or Hb bind O2 more tightly

Back 12

Mb (curve is to the left)

Front 13

Does BPG promote O2 dumping at peripheral tissues?

Back 13

yes

Front 14

whats HbF

Back 14

fetal hemoglobin

Front 15

does HbF bind O2 more or less tightly than HbA (the hemoglobin found in RBCs)

and why?

Back 15

more tightly

This promotes the transfer of O2 from maternal HbA to fetal HbF across the placenta

Front 16

what happens to blood that is stored for transfusion?

what does this mean clinically?

what is the clinical solution?

Back 16

it loses the BPG from RBCs

for 24-48 hours Hb holds O2 much too tightly

BPG is charged and cannot cross the RBC membrane. The nucleoside Inosine is added to the blood which is uncharged, gets into RBCs and enters the PPP and is eventually converted to BPG

Front 17

why do H+ ions decrease Hb affinity for O2

Back 17

they protonate the histidine residues, salt linkages are formed that stabilize the deoxy form of Hb

Front 18

whats that Hemoglobin that binds glucose and is important for assessing diabetic patients?

Back 18

Hb A(1c) the Ic should be subscript

Front 19

how many peptide chains in Mb

Back 19

1

Front 20

חיה

Back 20

be alive, live

Front 21

whats the mechanism of sickle cell anemia

Back 21

A point mutation causes coding of valine instead of glutamate in position 6 of the Hb beta chain. The resulting abnormal Hb exhibits changes in solubility and molecular stability. These properties are responsible for the profound clinical expressions of the sickling syndromes.