Disease relevance of BDH1

• A plasmid has been constructed to express human heart (HH) BDH in Escherichia coli as a hexahistidine-tagged fusion protein (HH-Histag-BDH) [1].
• The mature form of human heart BDH has now been expressed in catalytically active form in insect cells (Sf9, Spodoptera frugiperda) transfected with BDH-cDNA in baculovirus [2].
• The gene coding for d-3-hydroxybutyrate dehydrogenase (HBDH) was cloned from Pseudomonas fragi [3].
• D(-)-3-hydroxybutyrate dehydrogenase (BDH; EC 1.1.1.30) from a poly(D(-)-3-hydroxybutyrate) (PHB) degrading bacterium, Acidovorax sp. SA1, was purified using Toyopearl DEAE-650M, red-Sepharose CL-4B, and Q Sepharose FF [4].
• The BDH of strain SA1 had high amino acid sequence homology to that of Ralstonia eutropha H16 [4].

High impact information on BDH1

• Heart tissue showed normal LDH and BDH activities, except for some cells surrounding blood vessels, which activity was minimally decreased [5].
• The HH-Histag-BDH-PC complex (and HH-BDH derived therefrom by enterokinase cleavage) has apparent Michaelis constants (K(m) values) for NAD(+), NADH, (R)-3-hydroxybutyrate (HOB), and acetoacetate (AcAc) similar to those for bovine heart or rat liver BDH [1].
• (R)-3-Hydroxybutyrate dehydrogenase (BDH) is a lipid-requiring mitochondrial enzyme with a specific requirement of phosphatidylcholine (PC) for function [1].
• A computed structural model of HH-BDH predicts the two active center sulfhydryls to be C69 (near the adenosine moiety of NAD) and C242 [1].

Biological context of BDH1

• Analysis of the primary sequence of BDH, as determined by molecular cloning, predicts that lipid binding and substrate specificity are contributed by the C-terminal third of the protein [Marks, A. R., McIntyre, J. O., Duncan, T. M., Erdjument-Bromage, H., Tempst, P., & Fleischer, S. (1992) J. Biol. Chem. 267, 15459-15463] [2].
• Thus, although C242 (in the C-terminal lipid binding domain of BDH) is close to the active site, it appears to be in a hydrophobic environment and only indirectly defines the substrate binding site at the catalytic center of BDH [1].

Anatomical context of BDH1

• Monoclonal antibodies (mAbs) have been used to study structure-function relationships of (R)-3-hydroxybutyrate dehydrogenase (BDH) (EC 1.1.1.30), a lipid-requiring mitochondrial membrane enzyme with an absolute and specific requirement for phosphatidylcholine (PC) for enzymic activity [6].
• The K(m)s for NAD+ and (R)-3-hydroxybutyrate (R-HOB) of expressed BDH are similar to those for bovine heart or rat liver BDH in mitochondria [2].
• D-beta-hydroxybutyrate dehydrogenase (BDH) (EC 1.1.1.30), a membrane enzyme, has been purified to homogeneity from dromedary (Camelus dromedarius) liver mitochondria [7].

Associations of BDH1 with chemical compounds

• The analogous pyrenyl-PE effects a similar maximal quenching of tryptophan fluorescence for both proteins but with approximately 15-fold lower (K(Q))(eff) (half-maximal quenching at approximately 1.5% pyrenyl-PE) referable to nonspecific interaction of pyrenyl-PE with HH-Histag-BDH or GST-CTBDH [8].
• In the first step, AcAc and pyruvate are completely reduced, using 3-hydroxybutyrate dehydrogenase (EC 1.1.1.30) and lactate dehydrogenase (EC 1.1.1.27) in the presence of excess NADH at pH 7.5, to beta-hydroxybutyrate and lactate, respectively [9].
• Phenylpyruvate as well as phenylalanine had no inhibitory effects on ketone-body-catabolizing enzymes, namely 3-hydroxybutyrate dehydrogenase, 3-oxo acid CoA-transferase and acetoacetyl-CoA thiolase, in rat brain [10].
• Use of terpene-based solvents (Hemo-De, Histoclear, and Shandon and BDH xylene substitutes) in place of xylene in the Ehrlich indole test [11].

Other interactions of BDH1

• This method was applied to the measurement of glucose-6-phosphate dehydrogenase (EC 1.1.1.49) and 3-hydroxybutyrate dehydrogenase (EC 1.1.1.30) along the various structures of the rabbit nephron, microdissected from fresh tissue slices [12].

Analytical, diagnostic and therapeutic context of BDH1

• With both sulfhydryls derivatized, BDH has minimal activity, but site-directed mutagenesis of C69 and/or C242 now shows that neither of these cysteines is required for PC activation or catalysis (the double mutant, C69A/C242A, is highly active with essentially normal kinetic parameters) [1].
• We conclude that enzyme histochemistry of LDH and BDH activity on cryostat sections is a useful tool for detecting irreversible myocardial cell damage as early as 2 h reperfusion after ischaemia of the pig heart [5].
• A chemiluminescence-flow injection analysis of serum 3-hydroxybutyrate using a bioreactor consisting of 3-hydroxybutyrate dehydrogenase and NADH oxidase [13].

References