Proteins and Polypeptides – Basics, Structures, Functions, and Properties
Each protein contains one or more polypeptide chain. The chemical properties and order of the amino acids determines the structure and function of the polypeptide.

Protein - Wikipedia
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues.

High Protein Foods: 18 Foods for High Protein Meals - Healthline
Protein is essential for cell structure, immune function, and hormone synthesis, and eating enough protein can help keep you feeling full and satisfied. High protein foods include chicken and...

Protein • The Nutrition Source
Protein is an essential macronutrient, but not all food sources of protein are created equal, and you may not need as much as you think. Learn the basics about protein and shaping your diet with healthy protein foods.

Protein (nutrient) - Wikipedia
From a nutritional perspective, the defining characteristic of protein is its amino acid composition. Protein content in foods is commonly measured based on nitrogen content, as nitrogen is a fundamental component of amino acids. Proteins are polymer chains made of amino acids linked by peptide bonds. [1]

Protein | Definition, Structure, & Classification | Britannica
A protein is a naturally occurring, extremely complex substance that consists of amino acidresidues joined by peptide bonds. Proteins are present in all living organisms and include many essential biological compounds such as enzymes, hormones, and antibodies.

What Are Proteins? Definition, Types & Examples
People generally say “protein” (or “dietary protein”) when talking about nutrition and “proteins” when discussing the science of how the individual molecules work within your body.

Protein - Better Health Channel
Protein is an important part of a healthy diet. Proteins are made up of chemical 'building blocks' called amino acids. Your body uses amino acids to build and repair muscles and bones and to make hormones and enzymes. They can also be used as an energy source.

Protein Intake — How Much Protein Should You Eat per Day?
Protein is incredibly important for your health, weight loss, and body composition. This article explains exactly how much protein you should eat.

Protein: Why Your Body Needs It - WebMD
Your body needs protein to stay healthy and work the way it should. More than 10,000 types are found in everything from your organs to your muscles and tissues to your bones, skin, and hair.