Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.1.34 (lipoprotein lipase)
 7,025 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We synthesized enantiomeric 1-O-alkyl-2,3-diacyl-sn-glycerol and 3-O-alkyl-1,2-diacyl-sn-glycerol containing pyrene as a fluorescent reporter and the trinitrophenylamino residue as a fluorescence quencher; both reporter groups were covalently bound to the omega end of the acyl chains at positions sn-2 and sn-3(1), respectively. The fluorescence of the intact substrate molecules was very low. Chemical or enzymic release of the fatty acyl chains lead to fluorescence dequenching. The rate of lipolysis could be measured from the time-dependent increase in fluorescence intensity. We used the respective substrates for the continuous determination of activity and stereopreference of four different microbial lipases from Chromobacterium viscosum, Candida rugosa, Pseudomonas sp., Rhizopus arrhizus, as well as cutinase from Fusarium solani and lipoprotein lipase from bovine milk. The stereopreference of the lipases depended, in general, on how the substrate was solubilized in the reaction medium. All lipases under investigation preferentially hydrolysed the sn-1 acyl ester bond, if the lipid analog was dispersed in albumin-containing Tris/HCl buffer in the absence of detergent or organic solvent. In mixtures of 1:1 (by vol.) water/ethanol, the enzymes showed higher activity toward the sn-3 acyl ester bond, except for lipoprotein lipase which preferred the sn-1 acyl isomer under all conditions tested. Different stereopreferences were observed with the different lipases if the substrate was solubilized by amphiphiles (micelles of N-dodecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate). C. rugosa lipase and F. solani cutinase showed high stereopreference for the sn-3 acyl ester, whereas Pseudomonas sp. lipase and C. viscosum lipase hydrolysed both enantiomers at similar rates. From spectroscopic studies, it can be inferred that the conformation of the fluorescent lipids is probably similar in water, mixtures of water and organic solvents, and in micelles. The possible effects of reaction conditions on substrate accessibility and enzyme conformation on stereoselectivity of the respective lipases are discussed.
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PMID:Inversion of lipase stereospecificity for fluorogenic alkyldiacyl glycerols. Effect of substrate solubilization. 762 84

Aspergillus oryzae IFO4202 produces at least two extracellular lipolytic enzymes L1 and L2 (cutinase, and mono- and diacylglycerol lipase, respectively). Southern hybridization of restriction enzyme-digested genomic DNA fragments with 23-mer oligonucleotides synthesized according to the amino acid sequence of the L2 as probe suggested the presence of the L2 gene (tentatively designated as mdlB) and an additional weakly hybridizing region. A fragment containing the genomic mdlB gene was cloned in Escherichia coli. Nucleotide sequencing of the fragment revealed an open reading frame, comprising 1021 nucleotides, which contains two introns (51 and 52 nucleotides). Putative polyadenylation signals were found 182 and 287 bp downstream of the stop codon. The deduced amino acid sequence of the mdlB gene corresponds to 306 amino acid residues including a leader sequence of 28 amino acids and is highly similar to that of the mdlA gene of Penicillium camembertii. Three residues presumed to form the catalytic triad (serine, aspartic acid and histidine) of lipases were also conserved.
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PMID:Cloning and nucleotide sequence of the mono- and diacylglycerol lipase gene (mdlB) of Aspergillus oryzae. 880 3

Aspergillus oryzae produces at least three extracellular lipolytic enzymes, L1, L2 and L3 (cutinase, mono- and diacylglycerol lipase, and triacylglycerol lipase, respectively). We cloned the triacylglycerol lipase gene (provisionally designated tglA) by screening a genomic library using a PCR product obtained with two degenerate oligonucleotide primers corresponding to amino acid sequences of L3 as probes. Nucleotide sequencing of the genomic DNA and cDNA revealed that the L3 gene (tglA) has an open reading frame comprising 954 nucleotides, which contains three introns of 47, 83 and 62 bp. The deduced amino acid sequence of the tglA gene corresponds to 254 amino acid residues including a signal sequence of 30 amino acids and, in spite of the difference in substrate specificity, it is homologous to those of cutinases from fungi. Three residues presumed to form the catalytic triad, Ser, Asp and His, are conserved. The cloned cDNA of the tglA gene was expressed in Escherichia coli, and enzyme assaying and zymography revealed that the cloned cDNA encodes a functional triacylglycerol lipase.
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PMID:Cloning and sequencing of the triacylglycerol lipase gene of Aspergillus oryzae and its expression in Escherichia coli. 1093 Jul 31