Definition of protein
1 : any of various naturally occurring extremely complex substances that consist of amino-acid residues joined by peptide bonds, contain the elements carbon, hydrogen, nitrogen, oxygen, usually sulfur, and occasionally other elements (such as phosphorus or iron), and include many essential biological compounds (such as enzymes, hormones, or antibodies)
2 : the total nitrogenous material in plant or animal substances
Examples of protein in a Sentence
You need more protein in your diet.
These foods are an excellent source of protein.
These foods have all of the essential proteins.
Recent Examples of protein from the Web
This hijacks a cell’s protein-making machinery, causing it to turn out components for new viruses.
The USDA banned banned the use of such protein supplements in cattle in 1997.
The 183-year-old Ruegenwalder Muehle Carl Mueller GmbH & Co. KG now produces veggie schnitzels, hams and sausages such as a pea-protein Leberwurst, which is normally made of pig liver.
Some of those rodents would develop antibodies against these proteins, becoming immune.
The germ is loaded with protein, B vitamins, several minerals, antioxidants, phytochemicals (biologically active compounds in plants) and essential fatty acids.
The more mutations, the greater the chance that at least one produces a foreign-looking protein that is a beacon for immune cells, Vogelstein explained.
While oil only heats and browns the food thermally, mayonnaise also browns food chemically – that golden-brown color – through the Maillard reaction, which requires sugars and proteins to work.
The star ingredient is a human keratin protein (discovered by scientists researching regenerative medicine for injuries) that allegedly works to plump each individual strand.
These example sentences are selected automatically from various online news sources to reflect current usage of the word 'protein.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.
PROTEIN Defined for English Language Learners
Definition of protein for English Language Learners
: a substance found in foods (such as meat, milk, eggs, and beans) that is an important part of the human diet
PROTEIN Defined for Kids
Definition of protein for Students
: a nutrient found in food (as meat, milk, eggs, and beans) that is made up of many amino acids joined together, is a necessary part of the diet, and is essential for normal cell structure and function
Medical Definition of protein
1: any of numerous naturally occurring extremely complex substances (as an enzyme or antibody) that consist of amino acid residues joined by peptide bonds, contain the elements carbon, hydrogen, nitrogen, oxygen, usually sulfur, and occasionally other elements (as phosphorus or iron), that are essential constituents of all living cells, that are synthesized from raw materials by plants but assimilated as separate amino acids by animals, that are both acidic and basic and usually colloidal in nature although many have been crystallized, and that are hydrolyzable by acids, alkalies, proteolytic enzymes, and putrefactive bacteria to polypeptides, to simpler peptides, and ultimately to alpha-amino acids
2: the total nitrogenous material in plant or animal substances; especially : crude protein
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