Opine

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Opine ( N- carboxyethyl-amino acids) are nitrogen-containing organic compounds from the group of dicarboxylic acids that are formed by a condensation reaction ( elimination of water ) of α- keto acids and amino acids .

synthesis

Opines are end products of anaerobic degradation and are created by binding pyruvate to an amino acid.

General presentation of opine synthesis. An α-keto acid is often pyruvate (R 1 = CH 3 ), which reductively condenses with an L -amino acid (e.g. L - alanine with R 2 = CH 3 ). Often the D -Opin (top) is formed stereoselectively , but with some enzymes also an L -Opin (below).

properties

In nature, opines occur mainly in marine invertebrates , but also in genetically modified plant cells . The transfection of the plant cells is triggered by agrobacteria , that is, the bacteria transfer the genes for opine synthesis into the plant cell. It is not possible for plants to utilize opines - however, they serve the bacteria living in plants as a source of carbon , nitrogen and energy. Each Agrobacterium strain induces and utilizes its own opines. The genes for opine synthesis are located on a special plasmid , the so-called Ti plasmid . So far, more than 30 different opines have been described. The first of these was isolated by Morizawa from the cephalopod Octopus octopodia as early as 1927 and was therefore called octopine. The first opine dehydrogenase was isolated in 1969 from the adductor muscle of the great clam ( Pecten maximus ).

The opines include, for example

The most important opines, however, are octopine and nopaline, condensates of arginine with pyruvate or α-ketoglutarate.

Octopine is found in genetically modified cells and in the muscle cells of certain types of mollusc , including octopuses . This is where the name Octopin comes from . Nopal is the French name for the prickly pear Opuntia ficus-indica . The compound nopaline was first found in tumors of this type of cactus.

See also

Individual evidence

  1. ^ Gerhard Heldmaier, Gerhard Neuweiler; Comparative animal physiology. Vol. 2: Vegetative Physiology; P. 49, ISBN 978-3540000679 .
  2. ↑ a b Ulrike Hergert; Findings on the evolution of invertebrate opine dehydrogenases, ISBN 978-3867274883 .
  3. ↑ Comparative thermodynamic analysis of the substrate binding to the recombinant octopine dehydrogenase from the clam, Pecten maximus, and to the lactate dehydrogenase from the pig muscle .