In chemistry, an ester is a functional group derived from an acid in which the hydrogen atom (H) of at least one acidic hydroxyl group of that acid is replaced by an organyl group. Analogues derived from oxygen replaced by other chalcogens belong to the ester category as well. According to some authors, organyl derivatives of acidic hydrogen of other acids are esters as well, but not according to the IUPAC.
Carbon compounds are defined as chemical substances containing carbon. More compounds of carbon exist than any other chemical element except for hydrogen. Organic carbon compounds are far more numerous than inorganic carbon compounds. In general bonds of carbon with other elements are covalent bonds. Carbon is tetravalent but carbon free radicals and carbenes occur as short-lived intermediates. Ions of carbon are carbocations and carbanions are also short-lived. An important carbon property is catenation as the ability to form long carbon chains and rings.
In chemistry, pyrophosphates are phosphorus oxyanions that contain two phosphorus atoms in a P−O−P linkage. A number of pyrophosphate salts exist, such as disodium pyrophosphate and tetrasodium pyrophosphate, among others. Often pyrophosphates are called diphosphates. The parent pyrophosphates are derived from partial or complete neutralization of pyrophosphoric acid. The pyrophosphate bond is also sometimes referred to as a phosphoanhydride bond, a naming convention which emphasizes the loss of water that occurs when two phosphates form a new P−O−P bond, and which mirrors the nomenclature for anhydrides of carboxylic acids. Pyrophosphates are found in ATP and other nucleotide triphosphates, which are important in biochemistry. The term pyrophosphate is also the name of esters formed by the condensation of a phosphorylated biological compound with inorganic phosphate, as for dimethylallyl pyrophosphate. This bond is also referred to as a high-energy phosphate bond.
An acidic oxide is an oxide that either produces an acidic solution upon addition to water, or acts as an acceptor of hydroxide ions effectively functioning as a Lewis acid. Acidic oxides will typically have a low pKa and may be inorganic or organic. A commonly encountered acidic oxide, carbon dioxide produces an acidic solution when dissolved.
An organic acid anhydride is an acid anhydride that is also an organic compound. An acid anhydride is a compound that has two acyl groups bonded to the same oxygen atom. A common type of organic acid anhydride is a carboxylic anhydride, where the parent acid is a carboxylic acid, the formula of the anhydride being (RC(O))2O. Symmetrical acid anhydrides of this type are named by replacing the word acid in the name of the parent carboxylic acid by the word anhydride. Thus, (CH3CO)2O is called acetic anhydride.Mixed (or unsymmetrical) acid anhydrides, such as acetic formic anhydride (see below), are known, whereby reaction occurs between two different carboxylic acids. Nomenclature of unsymmetrical acid anhydrides list the names of both of the reacted carboxylic acids before the word "anhydride" (for example, the dehydration reaction between benzoic acid and propanoic acid would yield "benzoic propanoic anhydride").
Manganese(VII) oxide (manganese heptoxide) is an inorganic compound with the formula Mn2O7. Manganese heptoxide is a volatile liquid with an oily consistency. It is a highly reactive and powerful oxidizer that reacts explosively with nearly any organic compound. It was first described in 1860. It is the acid anhydride of permanganic acid.
Inorganic pyrophosphatase is an enzyme that catalyzes the conversion of one ion of pyrophosphate to two phosphate ions. This is a highly exergonic reaction, and therefore can be coupled to unfavorable biochemical transformations in order to drive these transformations to completion. The functionality of this enzyme plays a critical role in lipid metabolism, calcium absorption and bone formation, and DNA synthesis, as well as other biochemical transformations.
In enzymology, an ADP-sugar diphosphatase (EC 3.6.1.21) is an enzyme that catalyzes the chemical reaction
In enzymology, a CDP-glycerol diphosphatase (EC 3.6.1.16) is an enzyme that catalyzes the chemical reaction
In enzymology, a dolichyldiphosphatase (EC 3.6.1.43) is an enzyme that catalyzes the chemical reaction
In enzymology, a FAD diphosphatase (EC 3.6.1.18) is an enzyme that catalyzes the chemical reaction
In enzymology, a m7G(5')pppN diphosphatase (EC 3.6.1.30) is an enzyme that catalyzes the chemical reaction
In enzymology, a NAD+ diphosphatase (EC 3.6.1.22) is an enzyme that catalyzes the chemical reaction
In enzymology, a nucleoside-diphosphatase (EC 3.6.1.6) is an enzyme that catalyzes the chemical reaction
In enzymology, a nucleoside-triphosphate diphosphatase (EC 3.6.1.19) is an enzyme that catalyzes the chemical reaction
In enzymology, a nucleotide diphosphatase (EC 3.6.1.9) is an enzyme that catalyzes the chemical reaction
In enzymology, a phosphoribosyl-ATP diphosphatase (EC 3.6.1.31) is an enzyme that catalyzes the chemical reaction
In enzymology, an undecaprenyl-diphosphatase (EC 3.6.1.27) is an enzyme that catalyzes the chemical reaction
An acid anhydride is a type of chemical compound derived by the removal of water molecules from an acid.
Members of the H+, Na+-translocating Pyrophosphatase (M+-PPase) Family (TC# 3.A.10) are found in the vacuolar (tonoplast) membranes of higher plants, algae, and protozoa, and in both bacteria and archaea. They are therefore ancient enzymes.
