Opine

Opines are low molecular weight compounds found in plant crown gall tumors or hairy root tumors produced by pathogenic bacteria of the genus Agrobacterium and Rhizobium. Opine biosynthesis is catalyzed by specific enzymes encoded by genes contained in a small segment of DNA (known as the T-DNA, for 'transfer DNA'), which is part of the Ti plasmid (in Agrobacterium) or Ri plasmid (in Rhizobium), inserted by the bacterium into the plant genome. The opines are used by the bacterium as an important energy, carbon and nitrogen source. Each strain of Agrobacterium and Rhizobium induces and catabolizes a specific set of opines, this set typifying the Ti plasmid and Ri plasmid. There are some 30 different opines described so far.



Chemical structure
Chemically, opines fall into two major structural classes:

1. The vast majority are secondary amine derivatives resulting from the reduction of the imine formed by condensation of an amino acid, either with a keto acid or a sugar. The first subcategory includes the opines from the nopaline and octopine families. The nopaline family (nopaline, nopalinic acid, leucinopine, glutaminopine, succinamopine) is formed when alpha-ketoglutarate serves as the keto substrate in the condensation reaction. The octopine family (octopine, octopinic acid, lysopine, histopine) is formed when pyruvate is involved in the condensation reaction. The second subcategory includes the mannityl family (mannopine, mannopinic acid, agropine, agropinic acid) and the chrysopine family (deoxy-fructosyl glutamate, deoxy-fructosyl glutamine, deoxy-fructosyl oxoproline and chrysopine) formed by the condensation of an amino-acid with mannose.

2. Agrocinopines form a small, separate class of opines. Chemically they are sugar-phosphodiesters. For example, agrocinopine A is a phosphodiester of sucrose and L-arabinose.

Nomenclature
The name opine comes from octopine, the first opine discovered in 1927, not in crown galls, but in octopus muscle. Nopaline comes from the identification of this molecule in tumors that appeared on "nopal", the Spanish and French names of Opuntia spp. cactus. According to Oxford English Dictionary, the word opine was first used in print in 1977. Usually, the name of newly discovered opines has the ending "-opine". Exceptions are nopaline and strombine. On the other hand, not all molecule names ending in "-opine" are opines. For example, atropine, stylopine, europine, and lycopine belong to different classes of molecules.

Other sources of opines
Opines and opine-like substances are not restricted to crown galls tumors. The very first opine discovered, octopine, was initially isolated from octopus muscle. Similar derivatives have been isolated from muscle tissue of certain marine invertebrates: alanopine, strombine, and tauropine. Opines like acetopine and nopaline can also be formed in normal callus and plant tissue as a result of arginine metabolism. Saccharopine is an intermediate in the metabolism of amino acid lysine and occurs in fungi, higher plants and mammals, including humans. The poisonous mushroom Clitocybe acromelalga is a source of four opine type amino acids: valinopine, epileucinopine, isoleucinopine and phenylalaninopine.

List of opines
This is an alphabetical list of some opines or opine-like compounds.

Acetopine (N2-(carboxymethyl)-arginine or demethyl-octopine) was isolated from cotton (Gossypium hirsutum) and soybean (Glycine max) callus. It wasn't found in plant tissues transformed by Agrobacterium and therefore it is not considered a "true" opine.
 * Acetopine

Agrocinopines (A-D) are a separate class of opines. They are sugar-phosphodiesters. Agrocinopine A is phosphodiester of sucrose and L-Arabinose. Agrocinopine B is the corresponding phosphodiester, in which the glucose has been hydrolyzed from the sucrose portion of agrocinopine A.
 * Agrocinopines

Agropine (1'-deoxy-D-mannitol-1'-yl)-L-glutamine,1',2'-lactone) was obtained from crown gall tumors. It is a member of the mannityl family. It is derived from mannopine through the formation of a lactone.
 * Agropine

Agropinic acid (N-1-(D-mannityl)-L-glutamic acid lactam) is produced by crown gall tumors. Belongs to the mannityl family. It is formed by lactamization of agropine.
 * Agropinic acid

Beta-alanopine (2,2'-iminodipropionic acid or L-alanine, N-(1-carboxyethyl)-) and meso-alanopine (meso-N-(1-carboxyethyl)-alanine) were isolated from marine invertebrates. Structurally it is a member of the octopine family.
 * Alanopine

See succinamopine
 * Asparaginopine

Chrysopine (d-lactone of N-1-deoxy-D-fructosyl-L-glutamine) was first obtained from fig tree and chrysanthemum crown gall tumors. It is the deoxyfructosyl analog of agropine.
 * Chrysopine

Cucumopine (4,6-dicarboxy-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-4-propanoic acid) was found in grapevine crown gall tumours and carrot hairy-root cultures.
 * Cucumopine

Epileucinopine (N-(1-carboxy-3-methylbutyl)glutamic acid or N2-(1,3-dicarboxypropyl)leucine) was isolated from the poisonous mushroom Clitocybe acromelalga.
 * Epileucinopine

Glutaminopine (N2-(D-1,3-dicarboxypropyl) derivative of glutamine) is a member of the nopaline family isolated from crown gall tumors.
 * Glutaminopine

Heliopine (also named vitopine) (N2 -(1-carboxyethyl)glutamine) was obtained from crown gall tumors.
 * Heliopine

Histopine (N-(D-1-carboxyethyl)histidine) is a member of the octopine family found in crown gall tumors.
 * Histopine

Isoleucinopine (N-(1-carboxy-2-methylbutyl)glutamic acid or N-(1,3-dicarboxypropyl)isoleucine) was isolated from the poisonous mushroom Clitocybe acromelalga.
 * Isoleucinopine

Leucinopine (N2-(D-1,3-dicarboxypropyl) derivative of leucine) is a member of the nopaline family isolated from crown gall tumors.
 * Leucinopine

Lysopine (N2-(D-1-carboxyethyl)-L-lysine) is a member of the octopine family found in crown gall tumors.
 * Lysopine

Mannopine (N-1-(D-mannityl)-L-glutamine) is found in crown gall tumors. It is the head member of the mannityl family of opines.
 * Mannopine

Mannopinic acid (N-1-(D-mannityl)-L-glutamic acid) was isolated from crown gall tumors. Belongs to the mannityl family.
 * Mannopinic acid

Methiopine (N-[1-D-(carboxyl)ethyl]-L-methionine) was found in crown gall tumors.
 * Methiopine

Mikimopine (4-epimer of cucumopine) was first isolated from tobacco crow gall tumors.
 * Mikimopine

Nopaline (N2-(D-1,3-dicarboxypropyl)-L-arginine) was first isolated from crown gall tumors. It is the head member of the nopaline family of opines. It was also found in certain nontransformed plant tissues as a result of arginine metabolism
 * Nopaline

Nopalinic acid (also named ornaline) (N2-(D-1,3-dicarboxypropyl)-L-ornithine) is a member of the nopaline family found in crown gall tumors.
 * Nopalinic acid

Octopine (N2-(D-1-carboxyethyl)-L-arginine) is the first opine discovered in 1927 in octopus muscle and later in crown gall tumors. It is also found in other cephalopod species and lamellibranchs. It is the head member of the octopine family of opines.
 * Octopine

Octopinic acid (N2-(D-1-carboxyethyl)-L-ornithine) is a member of the octopine family isolated from crown gall tumors.
 * Octopinic acid

See nopalinic acid
 * Ornaline

Phenylalaninopine (N-(1-carboxy-2-phenylethyl)glutamic acid) was isolated from the poisonous mushroom Clitocybe acromelalga.
 * Phenylalaninopine

Rideopine (N-(4'-aminobutyl)-D-glutamic acid) is an opine-like molecule derived from putrescine. It is obtained from crown gall tumors.
 * Rideopine

Although not found in crown gall tumors, saccharopine (epsilon-N-(L-glutar-2-yl)-L-lysine) is chemically similar to "true" opines. It is formed by condensation of lysine and alpha-ketoglutarate. Saccharopine is an intermediate in the metabolism of amino acid lysine and occurs in fungi, higher plants and mammals, including man.
 * Saccharopine

Santhopine is the deoxyfructosyl analog of mannopine. It is a naturally occurring compound found in rotting fruits and vegetables. It was also isolated from crown gall tumors.
 * Santhopine

Strombine (Methylimidodiacetic acid or N-(D-1-carboxyethyl)-glycine) was first isolated from the gastropod mollusk Strombus. It acts as a fish attractant. Structurally it is a member of the octopine family.
 * Strombine

Succinamopine (also named asparaginopine) (N-(3-amino-1-carboxy-3-oxopropyl)glutamic acid) is a member of the nopaline family isolated from crown gall tumors. Its structure is analogous to that of nopaline, with asparagine replacing arginine.
 * Succinamopine

Tauropine (N-(D-1-carboxyethyl)-taurine) was found in some marine invertebrates. It is also called rhodoic acid. Structurally it is a member of the octopine family.
 * Tauropine

Valinopine (N-(1-carboxy-2-methylpropyl)glutamic acid or N-(1,3-dicarboxypropyl)valine) was isolated from the poisonous mushroom Clitocybe acromelalga.
 * Valinopine

See heliopine
 * Vitopine