Octopine

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Structural formula
Structural formula of octopine
D- octopine
General
Surname Octopine
other names
  • N 2 - (1-carboxyethyl) -N 5 - (diaminomethylene) ornithine ( IUPAC )
  • N a - (1-carboxyethyl) arginine
  • N 2 - ( D -1-carboxyethyl) - L -arginine
  • 2- (1-carboxy-ethylamino) -5-guanidino-pentanoic acid
  • 2- (1-carboxy-ethylamino) -5-guanidino-valeric acid
Molecular formula C 9 H 18 N 4 O 4
Brief description

white to brownish solid

External identifiers / databases
CAS number 34522-32-2
PubChem 427
ChemSpider 414
Wikidata Q2013941
properties
Molar mass 246.27 g mol −1
Physical state

firmly

Melting point

283-284 ° C

safety instructions
GHS hazard labeling
no classification available
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

D- octopine is a guanidine derivative . It was made from muscle tissue of various invertebrates , such as B. Octopus , Pecten maximus or Sipunculus nudus isolated, where it is a functional analogue of lactic acid (lactate).

history

Octopine is the first isolated Opin . It owes its name to Octopus octopodia , from which it was extracted in 1927.

biosynthesis

D- octopine is formed by a stereoselective NADH -dependent octopine dehydrogenase ( EC  1.5.1.11 ) from pyruvate and L - arginine via reductive condensation . L- arginine itself is obtained from phospho- L -arginine. As a result, the reduced nicotinamide adenine dinucleotide NADH that occurs during glycolysis can be reoxidized, so that NAD + is formed. This corresponds to lactic acid fermentation , in which pyruvate is reduced to L- lactate.

Synthesis of D- octopine from pyruvate and L-arginine, catalyzed by octopine dehydrogenase (ODH)

The reaction is also reversible: NADH can be formed again from NAD + and D- octopine can be split into pyruvate and L - arginine .

meaning

Squids need to be able to move quickly when they escape or attack, which requires a lot of energy in the form of ATP . However, the necessary ATP cannot be obtained from aerobic respiration because oxygen cannot get into the cells quickly enough. In squids, a special muscle is responsible for rapid locomotion, which draws energy from anaerobic glycolysis pathways through the formation of D- octopine.

For a long time it was anticipated that, in contrast to lactic acid fermentation, D- octopine, as a weak acid, does not contribute to the acidification of the cell ( acidosis ). This can be countered by the fact that D- octopine, in contrast to lactate, cannot leave the intracellular space and thus accumulates in larger quantities. Finally, the biochemical formation of D- octopine also leads to acidosis.

See also

Individual evidence

  1. ↑ a b sheet octopine from Acros, accessed on 26 February, 2010.
  2. ↑ This substance has either not yet been classified with regard to its hazardousness or a reliable and citable source has not yet been found.
  3. ↑ Morizawa, K. (1927): About the extracts from Octopus octopodia . In: Acta Schol. Med. Kyoto 10 , 285-298.
  4. ↑ Smits, SH. et al. (2008): A structural basis for substrate selectivity and stereoselectivity in octopine dehydrogenase from Pecten maximus. In: J Mol Biol. 381 (1); 200-211; PMID 18599075 ; doi: 10.1016 / j.jmb.2008.06.003 .
  5. ↑ a b Pörtner, HO. (2002): Environmental and functional limits to muscular exercise and body size in marine invertebrate athletes . In: Comp Biochem Physiol A Mol Integr Physiol . 133 (2); 303-321; PMID 12208302 ; doi: 10.1016 / S1095-6433 (02) 00162-9 .