haemoglobin 2: haemoglobin

Question 1

what is a normal concentration of red blood cells?

Answer 1

120-165g/L

Question 2

when does haemoglobin synthesis occur?

Answer 2

during development of RBS (65% erythroblast stage 35% reticulocyte stage)

Question 3

what is the structure of haemoglobin?

Answer 3

2𝛂2𝛃 chains (foetal = 𝛂+𝛄) + 4 haem molecules with iron atom

Question 4

where is haem synthesised?

Answer 4

mitochondria - iron enters cell bound to transferrin -> vesicle -> mitochondria

Question 5

where is globin synthesised?

Answer 5

cytosol

Question 6

what is the structure of haem?

Answer 6

protoporphyrin ring with central iron atom (ferroprotoporphyrin), iron usually in ferrous Fe2+ form and combines reversibly with oxygen

Question 7

which enzyme regulates rate of haem production?

Answer 7

d-ALAS (∂ aminolevulinic acid synthase)

Question 8

how many functional globin genes are there?

Answer 8

8 arranged in 2 clusters - 𝛃 cluster on short arm of Chr11 (𝛃,,∂&E genes) & a cluster (a&Cglobin genes) on short arm of Chr16

Question 9

what are the normal adult haemoglobins?

Answer 9

HbA (𝛂2𝛃2) - 96-98%, HbA2 (𝛂2d2) - 1.5-3.2%, HbF (𝛂2𝛄2) - 0.5-0.8%

Question 10

on HPLC what order (from left to right) do the haemoglobin peaks appear?

Answer 10

F->A->A2

Question 11

what is the structure of globin?

Answer 11

primary: 𝛂=144aa, non𝛂>146aa
secondary: helical arrangement
tertiary: spherical shape with hydrophilic surface & hydrophobic core + haem pocket