Jacqueline isolated an interesting new protein from the broth of a yeast culture. After purification of the protein, she requested an amino acid analysis and found that the protein contained 0.48 % tryptophan by weight (tryptophan Mr=204).

a. Calculate the minimum molecular weight of the protein (i. e., assuming there is only one tryptophan residue per protein molecule).

b. Size-exclusion chromatography of the protein gave a molecular weight estimate of 53500. How many tryptophan residues are present in a molecule of the new protein?

Question

Shasta

Chemistry

14 February, 18:42

Jacqueline isolated an interesting new protein from the broth of a yeast culture. After purification of the protein, she requested an amino acid analysis and found that the protein contained 0.48 % tryptophan by weight (tryptophan Mr=204).

a. Calculate the minimum molecular weight of the protein (i. e., assuming there is only one tryptophan residue per protein molecule).

b. Size-exclusion chromatography of the protein gave a molecular weight estimate of 53500. How many tryptophan residues are present in a molecule of the new protein?

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Answers (1)

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Obie · Answer 1

a) minimum molecular weight of the protein = 42500g

b) new protein contains 262.25 molecules of tryptophan

Explanation:

a) if 0.48 % by weight of tryptophan has the molecular weight=204g

It implies that the molecular weight of the 100% protein will be 100*204/0.48=42500g of protein as the minimum molecular weight of the protein

b) new protein Molecular weight = 53500

1-molecule of tryptophan has Mm = 204,

Hence 53500/204 = 262.25 molecules of tryptophan in the new protein