protein

noun

pro·​tein ˈprō-ˌtēn 

also

ˈprō-tē-ən 

plural proteins

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

3

: a food (such as meat or tofu) that is rich in protein

Having grown up with brisket or roasted chicken as the protein of choice at a Chanukah table, I was intrigued to find that Italian Jews traditionally celebrate the Festival of Lights with a special fried chicken recipe and wanted to give it a try.

—Sophie Panzer

There are 10 sandwiches to choose from, with different proteins like sausage, salami and mortadella.

—Cesar Hernandez

With plant proteins such as nuts or soy foods, we get good amounts of fiber and polyunsaturated fats …

—Walter Willett

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 on the Web

Cheese has some health benefits since the dairy product is full of protein, calcium, vitamin A and B-complex vitamins, the American Kennel Club reports. —Olivia Munson, USA TODAY, 21 Dec. 2024

Next, researchers appraised the concentration of 3,000 proteins in the participants’ blood, to determine which proteins—delivered to the brain via blood vessels—were associated with brain age. —Gayoung Lee, Smithsonian Magazine, 20 Dec. 2024

To meet the new definition of healthy, foods must contain a minimum amount of protein, whole grains, fruit, vegetables or fat-free or low-fat dairy, the FDA said. —Karen Kaplan, Los Angeles Times, 20 Dec. 2024

Individual needs vary, but dietitians BHG has spoken to recently generally recommend about 1 gram of protein per pound of body weight, spread fairly evenly throughout the day. —Karla Walsh, Better Homes & Gardens, 20 Dec. 2024

Word History

Etymology

borrowed from French protéine, from Late Greek prōteîos "of the first quality" (from Greek prôtos "first, foremost" + -eios, adjective suffix, originally from s-stems) + -ine -ine entry 1 — more at proto-

Note: The term protein was introduced by the Dutch chemist Johannes Gerardus Mulder (1802-80), as French protéine in the article "Sur la composition de quelques substances animales" (Bulletin des sciences physiques et naturelles en Néerlande, vol. 1 [1838], pp. 104-19), and as Dutch protein in the article "Over Proteine en hare Verbindingen en Ontleidingsproducten" (Natuur- en scheikundig Archief, vol. 6 [1838], pp. 87-162). Though Mulder in the beginning of the papers expresses gratitude to Jöns Jakob berzelius for his support, he does not mention any connection between Berzelius and the novel word. In the twentieth century, however, it was discovered that Berzelius had suggested the word to Mulder in a letter written July 10, 1838: "Le nom protéine que je vous propose pour l'oxyde organique de la fibrine et de l'albumine, je voulais le dériver de πρωτειος, parce qu'il paraît être la substance primitive ou principale de la nutrition animale que les plantes préparent pour les herbivores et que ceux-ci fournissent ensuite aux carnassiers." ("The name protein, which I propose for the organic oxide of fibrin and albumin, I wish to derive from prōteios, because it appears to be the primitive or principal substance of animal nutrition, which plants prepare for herbivores, and which the latter then provide for carnivores." — quoted in H.B. Vickery, "The origin of the word protein," Yale Journal of Biology and Medicine, vol. 22, no. 5 [May, 1950], pp. 387-93.) In the French article, Mulder glosses the word prōteîos with Latin primarius "primary": "The organic material, being a general principal of all the constituent parts of the animal body and being found, as we will see later, in the vegetable kingdom, could be named protein from prōteîos …" ("La matière organique, étant un principe général de toutes les parties constituantes du corps animal, et se trouvant, comme nous verrons tantôt, dans le règne végétal, pourrait se nommer Protéine de πρωτεῖος primarius.") This appears to be Mulder's own interpretation of the Greek word, as the leading Greek dictionary of the time, Franz Passow's Handwörterbuch der griechischen Sprache (4. Ausgabe, 1831) defines it only as a masculine noun: "first rank, first place, primacy, priority" ("erster Rang, erster Platz, Vorrang, Vorzug"). For details, see the article by H.B. Vickery cited above and Harold Hartley, "Origin of the Word 'Protein'," Nature, vol. 168, issue 4267 (August 11, 1951), p. 244.

First Known Use

1886, in the meaning defined at sense 1

Phrases Containing protein

• amyloid beta protein
• Bence-Jones protein
• beta-amyloid protein
• conjugated protein
• C-reactive protein
• fish protein concentrate
• G protein
• heat shock protein
• prion protein
• protein C
• protein kinase
• protein kinase C
• protein S
• silver protein
• simple protein
• spike protein
• S protein
• textured vegetable protein

Kids Definition

protein

noun

pro·​tein ˈprō-ˌtēn  ˈprōt-ē-ən 

: any of numerous substances that consist of chains of amino acids, contain the elements carbon, hydrogen, nitrogen, oxygen, and often sulfur, include many compounds (as enzymes and hormones) essential for life, and are supplied by various foods (as meat, milk, eggs, nuts, and beans)

proteinaceous

ˌprōt-ᵊn-ˈā-shəs

ˌprō-ˌtēn-

ˌprōt-ē-ən-

adjective

Medical Definition

protein

noun

pro·​tein ˈprō-ˌtēn  ˈprōt-ē-ən 

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