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| Title: | Isolation and some properties of malic enzyme from the abdomen muscle of Antarctic krill Euphausia superba. |
| Authors: | Napierska, Dorota
Skorkowski, Edward F. |
| ASFA Terms: | Enzymes
Kinetic energy
Muscles
Abdomen
Oceanography |
| Issue Date: | 2001 |
| Publisher: | Sea Fisheries Institute in Gdynia |
| Citation: | Bulletin of the Sea Fisheries Institute, Gdynia, 1. p. 31-44 |
| Abstract: | Malic enzyme (EC 1.1.1.40) was purified about 1800-fold from the abdomen muscle of
Euphausia superba to a specific activity of 20.3 mmol · min-1 per mg protein. The molecular weight
of the native malic enzyme was determined to be 270,000. The Km values determined at pH 7.2 for
decarboxylation reaction for malate and NADP+ were 0.229 mM and 10.6 mM, respectively. The
Km values for carboxylation reaction for pyruvate, NADPH and bicarbonate were 5 mM, 25.8 mM
and 12 mM, respectively. The effect of temperature on apparent Km for malate was studied. The
minimum Km appeared at 0oC, the ambient temperature of the species. The optimum pH for the
decarboxylation reaction was between 7.0 and 8.0 and varied with the malate concentration. The
enzyme showed substrate inhibition at a high malate concentration for the oxidative decarboxylation
reaction at pH 7.0. The optimum pH for the carboxylation reaction was between 6.5 and 7.0
and varied with the pyruvate concentration. The heat stability of the purified malic enzyme of
Antarctic krill E. superba was determined and compared with heat stability of the purified malic
enzyme from the Baltic shrimp Crangon crangon abdomen muscle. The enzymes lost their activities
at about 34oC and 65oC, respectively. |
| URI: | http://www.ceemar.org/dspace/handle/11099/463 |
| Related document: | http://www.mir.gdynia.pl/pliki/osrodek/biuletyn/biulet1-01.pdf |
| ISSN: | 1429-2335 |
| Appears in Collections: | Bulletin of the Sea Fisheries Institute
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