NAD-preferring malic enzyme: localization, regulation and its potential role in herring (Clupea harengus) sperm cells

Natalia Niedźwiecka , Jadwiga Gronczewska , Edward Skorkowski


Herring spermatozoa exhibit a high activity of NAD-preferring malic enzyme (NAD-ME). This enzyme is involved in the generation of NADH or NADPH in the decarboxylation of malate to form pyruvate and requires some divalent cations to express its activity. In order to confirm that NAD-ME isolated from herring sperm cells is localized in mitochondria, we performed immunofluorescent analysis and assayed spectrophotometrically the malic enzyme reaction. Production of polyclonal rabbit antibodies against NAD-ME from herring spermatozoa enabled identification of mitochondrial localization of this enzyme inside herring spermatozoa. The kinetic studies revealed that NAD-ME was competitively inhibited by ATP up to tenfold. Addition of fumarate reversed ATP-dependent inhibition of NAD-ME to 55 % of its maximum activity. The pH-dependent regulation of malic enzyme activity was also examined. Malic enzyme showed maximum activity at pH near 7.0 in all studied conditions. Finally, the role of malic enzyme activity regulation in mitochondria of herring sperm cells was discussed.
Author Natalia Niedźwiecka (FB / DME)
Natalia Niedźwiecka ,,
- Department of Molecular Evolution
, Jadwiga Gronczewska (FB / DME)
Jadwiga Gronczewska,,
- Department of Molecular Evolution
, Edward Skorkowski (FB / DME)
Edward Skorkowski,,
- Department of Molecular Evolution
Journal seriesFish Physiology and Biochemistry, ISSN 0920-1742, (A 20 pkt)
Issue year2017
Publication size in sheets0.5
Keywords in EnglishNAD-ME, immunolocalization, mitochondria, ATP, herring sperm
ASJC Classification2700 General Medicine; 1104 Aquatic Science; 1303 Biochemistry; 1314 Physiology
Languageen angielski
Not used for evaluationyes
Score (nominal)0
Publication indicators WoS Citations = 6; Scopus SNIP (Source Normalised Impact per Paper): 2017 = 0.917; WoS Impact Factor: 2017 = 1.735 (2) - 2017=2.061 (5)
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UwagiArtykuł został zgłoszony do parametryzacji za lata 2013-2016
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