Fundamentals of Biochemistry - Filippovich, Y. B. 1999

Proteins
Elemental Composition of Proteins

Proteins (from the Greek protos meaning 'first' or 'principal') are high-molecular-weight Organic compounds characterized by a strictly defined elemental composition, which break down into Amino Acids upon Hydrolysis.

They contain (%): carbon — 50–55, hydrogen — 6.5–7.3, nitrogen — 15–18, oxygen — 21–24, sulfur — up to 2.4, and ash — up to 0.5. A particularly diagnostic indicator is the nitrogen percentage. In most cases, it is 16%, which is why protein content in feed and foodstuffs is frequently calculated based on protein nitrogen levels. To do this, the percentage of protein nitrogen in the sample is multiplied by a conversion factor of 6.25, derived from the calculation: 100 : 16 = 6.25.



Last update: 06/08/2026

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