The number of disulphide linkages present in insulin are

$\begin {array} {1 1} (A)\;3 & \quad (B)\;4 \\ (C)\;1 & \quad (D)\;2 \end {array}$

Insulin is composed of two chains it has 2 disulphide linkages

Insulin has 3 disulphide bridges
The number of disulphide bridges in the whole of insulin molecule is three because there are two bridges between alpha n beta chain and in alpha chain there is an intra disulphide bridge between aa 6 and aa 11. Intet disulphide bridges occur between 10th aa of both chains and at 20th aa of alphachain with 19th aa of beta chain.
Ans : (A)
answered Mar 31, 2014
edited Oct 5, 2017 by meena.p