title: Strombine dehydrogenase in the demosponge Suberites domuncula: characterization and kinetic properties of the enzyme crucial for anaerobic metabolism.
abstract: Previously, the cDNA and the respective gene for a presumed tauropine dehydrogenase (TaDH) from Suberites domuncula (GenBank accession nos. AM712888, AM712889) had been annotated. The conclusion that the sequences encode a TaDH had been inferred from the 68% identity with the TaDH protein from the marine demosponge Halichondria japonica. However, subsequent enzymatic assays shown here indicate that the presumed S. domuncula opine dehydrogenase is in fact a strombine dehydrogenase (StDH). The enzyme StDH is highly specific for glycine and is inhibited by an excess of the substrate pyruvate. Besides kinetic data, we report in this study also on the predicted tertiary and quaternary structure of the sponge StDH. It is concluded that the dimer (75 kDa) has a novel structure, distinguishing it from other known marine invertebrate OpDHs that exist as monomers.
authors.affiliation: Institut für Physiologische Chemie, Abteilung Angewandte Molekularbiologie, Universität Mainz, Duesbergweg 6, D-55099 Mainz, Germany. bplese@irb.hr
authors.forename: Bruna
authors.initials: B
authors.lastname: Plese
authors.forename: Heinz C
authors.initials: HC
authors.lastname: Schröder
authors.forename: Vladislav A
authors.initials: VA
authors.lastname: Grebenjuk
authors.forename: Gerhard
authors.initials: G
authors.lastname: Wegener
authors.forename: David
authors.initials: D
authors.lastname: Brandt
authors.forename: Filipe
authors.initials: F
authors.lastname: Natalio
authors.forename: Werner E G
authors.initials: WE
authors.lastname: Müller
mesh_terms: D000693:Anaerobiosis; D000818:Animals; D005260:Female; D005998:Glycine / Q000378:metabolism; D007700:Kinetics; D008958:Models, Molecular; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000378:metabolism*; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D019289:Pyruvic Acid / Q000378:metabolism / Q000494:pharmacology; D047233:Suberites / Q000201:enzymology* / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D019289:Pyruvic Acid; D000587:Oxidoreductases Acting on CH-NH Group Donors; C036085:strombine dehydrogenase; D005998:Glycine