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The molar extinction coefficients of Trp and Tyr at 280 nm are 5690 and 1280 M–1.cm–1, respectively. The polypeptide chain of yeast alcohol dehydrogenase (37 kDa) contains 5 Trp and 14 Tyr residues. The absorbance at 280 nm of a 0.32 mg.mL–1 solution of yeast alcohol dehydrogenase measured in a cuvette of 1 cm pathlength will be _________.
(Assume that the molar extinction coefficient values for Trp and Tyr apply to these amino acids in the yeast alcohol dehydrogenase).
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- 0.37 to 0.43
- 0.37
- 0.23
- None of the above
Correct Option: A
Expected molar extinction sufficient of polypeptide chain E280nm =(5 × 5690) + (14 × 1280) = 46370 M–1 cm–1
Now, conc.of dehydrogenase
| C = | × 103 = 8.648 × 10–6 | |
| 37 |
∴ A / E = C ⇒ A = EC = 46370 × 8.648 × 10–6
A = 0.401
