1. Different extraction and purification techniques were employed for the separation of MG-lipase, TG-lipase and phospholipase A from rat liver microsomes. 2. Up to 60 per cent of the microsomal content of TG-lipase and phospholipase could be extracted with 1 M KCl or NaCl. MG-lipase was extracted more readily by detergents (e.g. emulphogen). 3. MG-lipase is more resistant to detergent and heat inactivation than TG-lipase and phospholipase A. It is retained, using the technique of affinity chromatography, on a column of CH-Sepharose coupled to monooleoylglycerol. In addition, MG-lipase was separated from TG-lipase by electrofocusing. 4. TG-lipase and phospholipase A were partially separated by gel filtration on Sephadex G-200 in the presence of 1 mM dithiothreitol and by chromatography on CH-Sepharose 4b. 5. On the basis of the present extraction and purification studies, it is concluded that mg-lipase is an enzyme protein distinct from TG-lipase and phospholipase A.
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http://dx.doi.org/10.1016/s0300-9084(77)80057-6 | DOI Listing |
J Hepatol
November 2024
Department of Molecular Genetics, University of Texas Southwestern Medical Center (UTSW), Dallas, TX 75390-9046, USA; Howard Hughes Medical Institute, UTSW, Dallas, TX 75390, USA; The Eugene McDermott Center for Human Growth and Development, UTSW, Dallas, TX, 75390, USA. Electronic address:
Background & Aims: PNPLA3(148M) (patatin-like phospholipase domain-containing protein 3) is the most impactful genetic risk factor for steatotic liver disease (SLD). A key unresolved issue is whether PNPLA3(148M) confers a loss- or gain-of-function. Here we test the hypothesis that PNPLA3 causes steatosis by sequestering ABHD5 (α/β hydrolase domain-containing protein 5), the cofactor of ATGL (adipose TG lipase), thus limiting mobilization of hepatic triglyceride (TG).
View Article and Find Full Text PDFSci Rep
January 2022
Department of Animal and Dairy Sciences, University of Wisconsin-Madison, 1675 Observatory Drive Rm 934B, Madison, WI, 53706, USA.
Knockdown of patatin-like phospholipase domain-containing protein 3 (PNPLA3) increased triglycerides (TG) in primary bovine hepatocytes, suggesting that PNPLA3 plays a causal role in hepatic TG clearing. In vivo, PNPLA3 abundance across the periparturient period is inversely related to hepatic TG accumulation and circulating fatty acid (FA) concentrations. The purpose of this research was to determine if PNPLA3, as well as other lipases, transcription factors, or FA-mediated genes, are regulated by FA mimicking liver lipid accumulation (ACCUM) and liver lipid clearing (RECOV) or singular FA physiologically found in dairy cows at 0.
View Article and Find Full Text PDFJ Lipid Res
August 2019
Research Group Molecular Physiology Max-Planck-Institut für Biophysikalische Chemie, Göttingen, Germany
Triglycerides (TGs) are the main energy storage form that accommodates changing organismal energy demands. In , the TG lipase Brummer is centrally important for body fat mobilization. Its gene () encodes the ortholog of mammalian adipose TG lipase, which becomes activated by α/β-hydrolase domain-containing 5 (ABHD5/CGI-58), one member of the paralogous gene pair, α/β-hydrolase domain-containing 4 () and In , the () gene encodes the single sequence-related protein to mammalian ABHD4/ABHD5 with unknown function.
View Article and Find Full Text PDFJ Biochem
November 2016
Department of Biochemistry.
DDHD2 has been reported to exhibit phospholipase A, triacylglycerol (TG) lipase and diacylglycerol (DG) lipase activities. However, the detailed enzymatic properties of DDHD2 have not yet been elucidated. In the current study, the substrate specificity of DDHD2 towards DG, TG and phosphatidic acid (PA) has been examined using highly purified recombinant rat DDHD2 (rDDHD2) with a liquid chromatography mass spectrometer.
View Article and Find Full Text PDFJ Lipid Res
December 2014
Wihuri Research Institute, 00290 Helsinki, Finland.
Human mast cells (MCs) contain TG-rich cytoplasmic lipid droplets (LDs) with high arachidonic acid (AA) content. Here, we investigated the functional role of adipose TG lipase (ATGL) in TG hydrolysis and the ensuing release of AA as substrate for eicosanoid generation by activated human primary MCs in culture. Silencing of ATGL in MCs by siRNAs induced the accumulation of neutral lipids in LDs.
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