The minimum molecular weight of insulin containing 3.4% sulphur is :

wt. of sulphur, S = 3.4 g; mol. wt. of insulin=100gmol−at. wt. of S = 32.For minimum mol. wt. of insulin, there should be at least one S-atom. Thus :For 3.4 g S, mol. wt. of insulin                                = 100∴ For 32 g S, mol. wt. of insulin=1003.4×32=941.176 g mol−