Answer to Question #328509 in Biochemistry for Hrithik

Question

The human hemoglobin is a tetrameric protein of about 64.5 KDa, consisting of two α-

chains and two β-chains tightly bound.

a) Calculate the number of amino acids present in the α-chains

b) What is the length of each β-chain?

c) What is the sum of the length of the two α-chains?

d) Find the length of the tetrameric protein hemoglobin assuming its all an alpha

helical structure.

Answer 1

1)Firstly, we should change KDa into Da and that’s 64 500 Da. Then divide 64 500 into 2 and get 32 250. Then use this formula: 32 250=(110•n) , just solving this linear equation we get n=293 ( the number of amino acids in two a-chains together)

2) each β-chain contains 146 amino acids residues. To calculate the length we should solve this: 146•0,36nm=52,56nm

3)The same principle is applied here 141•2•0,36nm=101,52nm-sum of the length of the two α-chains

4)So there are 574 amino acids residues in hemoglobin overall. Then we calculate amounts of turns by dividing 574 by 3,6(that aa per one turn of helix) and we get 159. Then we multiply 159 by 15A(Armstrong)and get 2392A. 1A=0.1nm So the length of the helix is 239.2nm