Tryptophan content of serum albumin

Tryptophan content of serum albumin was determined spectrophotometrically. The method used for the determination of tryptophan gave consistent results. Results show that the tryptophan contents of bovine and human serum albumin are significantly different from chicken serum albumin. Bovine and human serum albumins, however, are not significantly different from each other. A large difference in tryptophan content was found between two samples of chicken serum albumin. This suggests that the tryptophan content of serum albumin may not be constant for any given species. For these reasons, tryptophan content should not be used to estimate the molecular weight of serum albumin.