Enzyme

enzymologyenzymesenzymaticholoenzymeenzymaticallyapoproteinbiocatalystapoenzymeenzymatic activitybiocatalysts
Enzymes are both proteins and biological catalysts (biocatalysts).wikipedia
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Catalysis

catalyzescatalysescatalyst
Enzymes are both proteins and biological catalysts (biocatalysts).
Enzymes and other biocatalysts are often considered as a third category.

Metabolism

metabolicmetabolizedmetabolic pathways
Almost all metabolic processes in the cell need enzyme catalysis in order to occur at rates fast enough to sustain life.
These enzyme-catalyzed reactions allow organisms to grow and reproduce, maintain their structures, and respond to their environments.

Ribozyme

ribozymescatalytic properties of RNAcatalytic RNA
Other biocatalysts are catalytic RNA molecules, called ribozymes.
Ribozymes (ribonucleic acid enzymes) are RNA molecules that are capable of catalyzing specific biochemical reactions, including RNA splicing in gene expression, similar to the action of protein enzymes.

Enzyme catalysis

catalytic mechanisminduced fitenzymatic reaction
Almost all metabolic processes in the cell need enzyme catalysis in order to occur at rates fast enough to sustain life.
Enzyme catalysis is the increase in the rate of a process by a biological molecule, an "enzyme".

Pseudoenzyme

pseudoenzymeslack the active site residuespseudoenzyme analysis
The study of enzymes is called enzymology and a new field of pseudoenzyme analysis has recently grown up, recognising that during evolution, some enzymes have lost the ability to carry out biological catalysis, which is often reflected in their amino acid sequences and unusual 'pseudocatalytic' properties.
Pseudoenzymes are variants of enzymes (usually proteins) that are catalytically-deficient (usually inactive), meaning that they perform little or no enzyme catalysis.

Protein

proteinsproteinaceousstructural proteins
Enzymes are both proteins and biological catalysts (biocatalysts).
Many proteins are enzymes that catalyse biochemical reactions and are vital to metabolism.

Chemical reaction

reactionchemical reactionsreactions
Catalysts accelerate chemical reactions.
These reactions are often catalyzed by protein enzymes.

Orotidine 5'-phosphate decarboxylase

OMP decarboxylaseenzyme for the decarboxylationODC
An extreme example is orotidine 5'-phosphate decarboxylase, which allows a reaction that would otherwise take millions of years to occur in milliseconds.
Orotidine 5'-phosphate decarboxylase (OMP decarboxylase) or orotidylate decarboxylase is an enzyme involved in pyrimidine biosynthesis.

Metabolic pathway

metabolic pathwayspathwaypathways
Metabolic pathways depend upon enzymes to catalyze individual steps.
The reactants, products, and intermediates of an enzymatic reaction are known as metabolites, which are modified by a sequence of chemical reactions catalyzed by enzymes.

Papain

Accuzymemeat tenderizerpapayotin
Some household products use enzymes to speed up chemical reactions: enzymes in biological washing powders break down protein, starch or fat stains on clothes, and enzymes in meat tenderizer break down proteins into smaller molecules, making the meat easier to chew.
Papain, also known as papaya proteinase I, is a cysteine protease enzyme present in papaya (Carica papaya) and mountain papaya (Vasconcellea cundinamarcensis).

Enzyme activator

activatoractivatorsactivate
Enzyme activity can be affected by other molecules: inhibitors are molecules that decrease enzyme activity, and activators are molecules that increase activity.
Enzyme activators are molecules that bind to enzymes and increase their activity.

Reaction rate

raterate of reactionrates
Like all catalysts, enzymes increase the reaction rate by lowering its activation energy.
The concepts of chemical kinetics are applied in many disciplines, such as chemical engineering, enzymology and environmental engineering.

DNA polymerase

DNA polymerasespolymeraseDNA
Following Buchner's example, enzymes are usually named according to the reaction they carry out: the suffix -ase is combined with the name of the substrate (e.g., lactase is the enzyme that cleaves lactose) or to the type of reaction (e.g., DNA polymerase forms DNA polymers).
DNA polymerase is an enzyme that synthesizes DNA molecules from deoxyribonucleotides, the building blocks of DNA.

Lactase

LactaidLCTlactase enzyme
Following Buchner's example, enzymes are usually named according to the reaction they carry out: the suffix -ase is combined with the name of the substrate (e.g., lactase is the enzyme that cleaves lactose) or to the type of reaction (e.g., DNA polymerase forms DNA polymers).
Lactase is an enzyme produced by many organisms.

Saliva

salivationspittlespit
By the late 17th and early 18th centuries, the digestion of meat by stomach secretions and the conversion of starch to sugars by plant extracts and saliva were known but the mechanisms by which these occurred had not been identified.
In humans, saliva is 99.5% water plus electrolytes, mucus, white blood cells, epithelial cells (from which DNA can be extracted), enzymes (such as amylase and lipase), antimicrobial agents such as secretory IgA, and lysozymes.

Diastase

diastaticdiastatic malt
French chemist Anselme Payen was the first to discover an enzyme, diastase, in 1833.
A diastase (from Greek διάστασις, "separation") is any one of a group of enzymes that catalyses the breakdown of starch into maltose.

Catalase

catalase testcatalase-negativeCAT
In 1926, James B. Sumner showed that the enzyme urease was a pure protein and crystallized it; he did likewise for the enzyme catalase in 1937.
Catalase is a common enzyme found in nearly all living organisms exposed to oxygen (such as bacteria, plants, and animals).

Zymase

fermentation
He named the enzyme that brought about the fermentation of sucrose "zymase".
Zymase is an enzyme complex that catalyzes the fermentation of sugar into ethanol and carbon dioxide.

Wilhelm Kühne

Wilhelm KuhneKühne, Wilhelm (Willy) FriedrichWilly Kuhne
In 1877, German physiologist Wilhelm Kühne (1837–1900) first used the term enzyme, which comes from Greek ἔνζυμον, "leavened" or "in yeast", to describe this process.
Born in Hamburg, he is best known today for coining the word enzyme.

James B. Sumner

James Batcheller Sumner
In 1926, James B. Sumner showed that the enzyme urease was a pure protein and crystallized it; he did likewise for the enzyme catalase in 1937.
He discovered that enzymes can be crystallized, for which he shared the Nobel Prize in Chemistry in 1946 with John Howard Northrop and Wendell Meredith Stanley.

Urease

urease-positive
In 1926, James B. Sumner showed that the enzyme urease was a pure protein and crystallized it; he did likewise for the enzyme catalase in 1937.
These enzymes catalyze the hydrolysis of urea into carbon dioxide and ammonia:

Transferase

transferasesformyltransferasehydroxymethyltransferase
A transferase is any one of a class of enzymes that enact the transfer of specific functional groups (e.g. a methyl or glycosyl group) from one molecule (called the donor) to another (called the acceptor).

Hexokinase

Hexokinase IVhexokinase-2
For example, hexokinase (EC 2.7.1.1) is a transferase (EC 2) that adds a phosphate group (EC 2.7) to a hexose sugar, a molecule containing an alcohol group (EC 2.7.1).
A hexokinase is an enzyme that phosphorylates hexoses (six-carbon sugars), forming hexose phosphate.

Ethanol

alcoholbioethanolethyl alcohol
A few decades later, when studying the fermentation of sugar to alcohol by yeast, Louis Pasteur concluded that this fermentation was caused by a vital force contained within the yeast cells called "ferments", which were thought to function only within living organisms.
If ingested orally, ethanol is extensively metabolized by the liver, particularly via the enzyme CYP450.

Enzyme Commission number

EC numberECEC numbers
The International Union of Biochemistry and Molecular Biology have developed a nomenclature for enzymes, the EC numbers; each enzyme is described by a sequence of four numbers preceded by "EC", which stands for "Enzyme Commission".
The Enzyme Commission number (EC number) is a numerical classification scheme for enzymes, based on the chemical reactions they catalyze.