(a) Experimental results describing a protein's amino acid composition are useful for estimating the molecular weight (MW) of the entire protein. A quantitative amino acid analysis reveals that bovine cytochrome c contains 2% cysteine (r 121 ) by weight. Calculate the approximate molecular weight of bovine cytochrome c if there are 2 cysteine residues.
(b) Bovine chymotrypsinogen has a molecular weight of 25.6 kDa. Amino acid analysis shows that this enzyme is 9% alanine (r 89.1 ). Calculate how many alanine residues are present in a molecule of bovine chymotrypsinogen. Round your answer to the nearest whole number.