The nitrogen content of protein is approximately what percent?

• A. 12%
• B. 16%
• C. 18%
• D. 22%

Answer: (B)

Proteins contain nitrogen as a key part of their amino groups, and when you average across the many amino acids that make up proteins, nitrogen accounts for about one-sixth of the protein’s mass. That works out to roughly 16 percent. This is why nitrogen measurements can be used to estimate protein content, by applying the conversion factor that 1 gram of nitrogen corresponds to about 6.25 grams of protein. So the nitrogen content of protein is approximately 16 percent.