Manual

Table 2. Comparison of Bio-Rad, Lowry, and Biuret Protein
Assays for 23 Proteins
All assays were performed on appropriate dilutions of gravimetrically pre-
pared 10 mg/ml solutions of commercially obtained proteins. Standards
were as described in the text.
Assay Results (Protein mg/ml)
Biuret Lowry Bio-Rad
1. Alcohol dehydrogenase 5.8 5.0 7.8
2. α-Amylase 6.8 6.0 8.3
3. Bovine serum albumin 9.7 8.4 21.1
4. Carbonic anhydrase 8.8 8.9 13.0
5. Catalase 7.6 6.3 9.7
6. α-Chymotrypsin 9.4 11.6 7.8
7. Cytochrome c* 25.7 11.3 25.3
8. Ovalbumin 10.2 10.1 9.4
9. Fibrinogen 6.2 7.3 7.8
10. Gamma globulin (rabbit) 9.4 11.8 8.0
11. β-Galactosidase 9.5 9.9 7.9
12. Hemoglobin (bovine)* 16.2 8.3 19.9
13. Histones 9.7 9.2 15.8
14. Hemocyanin 6.6 5.4 9.2
15. Lysozyme 10.4 12.6 9.9
16. Myoglobin* 13.7 7.9 20.7
17. Ovomucoid 7.8 8.3 5.9
18. Pepsin 9.8 12.4 4.1
19. Ribonuclease 11.8 15.9 5.3
20. Trypsin inhibitor (soy) 9.1 10.3 6.1
21. Transferrin 8.5 9.0 12.6
22. Trypsin 11.4 15.5 4.9
23. Thyroglobulin 7.7 8.2 9.3
Average 10.1 9.5 10.9
*Average 8.8 9.6 9.2
* The second average eliminates from the figures the values for the three colored proteins shown by
asterisks.
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