Protein Wiki - What is the protein?
Proteins are large biomolecules, or macromolecules, consisting of one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, providing structure to cells and organisms, and transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the nucleotide sequence of their genes, and which usually results in protein folding into a specific three-dimensional structure that determines its activity. A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called peptides, or sometimes oligopeptides. The individual amino acid residues are bonded together by peptide bonds and adjacent amino acid residues. The sequence of amino acid residues in a protein is defined by the sequence of a gene, which is encoded in the genetic code. In general, the genetic code specifies 20 standard amino acids; however, in certain organisms the genetic code can include selenocysteine and—in certain archaea—pyrrolysine. Shortly after or even during synthesis, the residues in a protein are often chemically modified by post-translational modification, which alters the physical and chemical properties, folding, stability, activity, and ultimately, the function of the proteins. Sometimes proteins have non-peptide groups attached, which can be called prosthetic groups or cofactors. Proteins can also work together to achieve a particular function, and they often associate to form stable protein complexes. Once formed, proteins only exist for a certain period and are then degraded and recycled by the cell's machinery through the process of protein turnover. A protein's lifespan is measured in terms of its half-life and covers a wide range. They can exist for minutes or years with an average lifespan of 1–2 days in mammalian cells. Abnormal or misfolded proteins are degraded more rapidly either due to being targeted for destruction or due to being unstable. Like other biological macromolecules such as polysaccharides and nucleic acids, proteins are essential parts of organisms and participate in virtually every process within cells. Many proteins are enzymes that catalyse biochemical reactions and are vital to metabolism. Proteins also have structural or mechanical functions, such as actin and myosin in muscle and the proteins in the cytoskeleton, which form a system of scaffolding that maintains cell shape. Other proteins are important in cell signaling, immune responses, cell adhesion, and the cell cycle. In animals, proteins are needed in the diet to provide the essential amino acids that cannot be synthesized. Digestion breaks the proteins down for use in the metabolism. Proteins may be purified from other cellular components using a variety of techniques such as ultracentrifugation, precipitation, electrophoresis, and chromatography; the advent of genetic engineering has made possible a number of methods to facilitate purification. Methods commonly used to study protein structure and function include immunohistochemistry, site-directed mutagenesis, X-ray crystallography, nuclear magnetic resonance and mass spectrometry..
What does the word protein mean? Find synonyms, antonyms and the meaning of the word protein in our free online dictionary! Find words starting with protein and anagrams of protein.
Definitions of "protein"
- Any of a group of complex organic macromolecules that contain carbon, hydrogen, oxygen, nitrogen, and usually sulfur and are composed of one or more chains of amino acids. Proteins are fundamental components of all living cells and include many substances, such as enzymes, hormones, and antibodies, that are necessary for the proper functioning of an organism. They are essential in the diet of animals for the growth and repair of tissue and can be obtained from foods such as meat, fish, eggs, milk, and legumes. noun
- Any of numerous large, complex naturally-produced molecules composed of one or more long chains of amino acids, in which the amino acid groups are held together by peptide bonds. noun
- One of three major classes of food or source of food energy (4 kcal/gram) abundant in animal-derived foods (ie: meat) and some vegetables, such as legumes. see carbohydrate and fat for the other two major classes noun
- In chemical analysis, the total nitrogenous material in vegetable or animal substances, obtained by multiplying the total nitrogen found by a factor, usually 6.25, assuming most proteids to contain approximately 16 per cent of nitrogen. noun
- any polymer of an amino acid joined by peptide (amide) bonds. Most natural proteins have alpha-amino acids as the monomeric constituents. All classical enzymes are composed of protein, and control most of the biochemical transformations carrie dout in living cells. They may be soluble, as casein, albumins, and other globular proteins, or insoluble (e. g. "structural proteins"), as collagen or keratin. "albumin", an older term for protein, is now used primarily to refer to certain specific soluble globular proteins found in eggs or blood serum, e.g. bovine serum albumin, the main soluble protein in teh serum of cattle, used as an enzymatically inert protein in biochemical research. noun
- A hypothetical substance formerly believed to be the essential nitrogenous constituent of food, and to exist in animal and vegetable albumin, fibrin, casein, and other bodies. noun
- Collectively, the nitrogenous components of food, sometimes excluding and sometimes including certain gelatinoid and amidic substances which are without nutritive value or possess it in an inferior degree. noun
- A trade-name for a dried preparation which consists essentially of the casein of milk: sold as a food material. noun
- any of a large group of nitrogenous organic compounds that are essential constituents of living cells; consist of polymers of amino acids; essential in the diet of animals for growth and for repair of tissues; can be obtained from meat and eggs and milk and legumes noun
The word "protein" in example sentences
A faulty beta-globin protein is made, leading to severe anemia.. [Poster-Medicine-1993]
Under the term protein are included the principal nitrogenous compounds which make bone, muscle and other material.. [No Animal Food and Nutrition and Diet with Vegetable Recipes]
They are remarkable high in protein, which is provided at a much higher efficiency rate than beef.. [Archive 2009-04-01]
Although the fluorescence emission spectrum of this protein is adequate for separation from DsRed, it tends to co-aggregate with DsRed and is far less bright.. [Archive 2005-10-01]
Unfortunately, this protein is an obligate tetramer, making it less suitable fur use as an epitope tag than PA-GFP.. [Archive 2005-10-01]
When this protein is activated, it and another protein, calcineurin, trigger the physical changes that muscle cells undergo after intense exercise.. [Boing Boing: April 7, 2002 - April 13, 2002 Archives]
It means that phosphate groups are coupled to a protein in such a way that the form and function of the protein is altered.. [Physiology or Medicine for 2000 - Press Release]
The biological properties of the protein is thereby altered.. [Physiology or Medicine 1992 - Press Release]
We are already developing leguminous plants for what we call protein banks.. [Castro Delivers Speech on ANAP Anniversary]
The first successful determination of the structure of a protein is the result of many years of persistent and zealous work, in which the final solution of the problem has been approached step by step.. [Nobel Prize in Chemistry 1958 - Presentation Speech]
In the USA, where persuasive food industry marketing has managed to make the word protein mean exactly the same as the word meat, we don’t lack protein.. [THE HIGH SCHOOL REUNION DIET]
The nicastrin protein is also a part of an enzyme called gamma-secretase, which is wedged in the cell’s membrane.. [Dallas Blog, Daily News, Dallas Politics, Opinion, and Commentary FrontBurner Blog D Magazine » Blog Archive » BIG NEWS ABOUT ALZHEIMER’S OUT OF UT SOUTHWESTERN]
Nixtamalization also very slightly improves the availability of protein from the corn, but not enough to overcome the protein deficency of the grain.. [Frijol---Frijoles]
Powder from hemp seeds is extremely high in protein and in omega-3 oils, now mostly gotten from fish.. [Harvey Wasserman: Hemp is the Hidden Key to Legal Marijuana]
Chickpea: A very strong tasting and smelling flour ground from dried chickpeas or garbanzo beans, high in protein and relatively nutrient dense and “creamy” flavoured.. [Archive 2009-07-01]
This specially prepared milk residue they called protein-free milk.. [The Vitamine Manual]
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