Question

If a protein that contains six tryptophan residues and three tyrosine residues, calculate the absorbance for 1 mg/ml sample at 280 nm in aqueous buffer given molecular weight is 14,313 da.

Answer 1

Explanation:

Answer:

A= (ε x c x l)

Now, the value of ε is given for Tryptophan and tyrosine residue but in a protein the effective value of ε will depend on the number of tryptophan and/or tyrosine residues

c= concentration in M

Therefore for first protein,

Effective ε= 6×1200= 7200 M-1cm-1

c= 1/30,000 M

l= path length= 1cm (in most cases)

A= 7200 x (1/30000) x 1

= 0.24

For second protein,

Effective ε= 1×5600= 5600 M-1cm-1

c= 1/60,000 M

l= path length= 1cm (in most cases)

A= 5600 x (1/60000) x 1

= 0.093