Incorporation of Sialic Acid into Sialidase-Treated Apolipoprotein of Human, Very Low Density Lipoprotein by a Pork Liver Sialyltransferase

1974 ◽  
Vol 52 (8) ◽  
pp. 655-664 ◽  
Author(s):  
Stephen Wetmore ◽  
Robert W. Mahley ◽  
W. Virgil Brown ◽  
Harry Schachter
Keyword(s):  
Low Density Lipoprotein ◽  
Liver Microsomes ◽  
Density Lipoprotein ◽  
Very Low Density Lipoprotein ◽  
Low Density ◽  
Ph Optimum ◽  
Acetylneuraminic Acid ◽  
Pork Liver ◽  
Terminal Galactose ◽  
Ovine Submaxillary Mucin

Pork liver microsomes are capable of catalyzing the incorporation of N-14C-acetylneuraminic acid from CMP-N-14C-acetylneuraminic acid into a sialidase-treated apolipoprotein (apoLP-Ala1) prepared from human, very low density lipoprotein and into sialidase-treated ovine submaxillary mucin. The pH optimum for the lipoprotein sialyltransferase is 5.8, and the Km values for CMP-N-acetylneuraminic acid, sialidase-treated apoLP-Ala1 and sialidase-treated ovine submaxillary mucin are, respectively, 0.04 mM, 0.04 mM, and 10 mM. Mixed substrate experiments indicate that the same sialyltransferase acts on both lipoprotein and mucin acceptors but that this enzyme is different from a previously described pork liver sialyltransferase which incorporates N-acetylneuraminic acid into linkage with the terminal galactose residues of sialidase-treated α1-acid glycoprotein. The radioactive product of the lipoprotein sialyltransferase releases, on treatment with alkaline borohydride, a reduced oligosaccharide tentatively identified as N-14C-acetylneuraminyl-N-acetylgalactosaminitol.

scholarly journals Overt and latent activities of diacylglycerol acytransferase in rat liver microsomes: possible roles in very-low-density lipoprotein triacylglycerol secretion

1997 ◽  
Vol 323 (1) ◽  
pp. 17-21 ◽  
Author(s):  
Mark R. OWEN ◽  
Clark C. CORSTORPHINE ◽  
Victor A. ZAMMIT
Keyword(s):  
Rat Liver ◽  
Low Density Lipoprotein ◽  
Mode Of Delivery ◽  
Liver Microsomes ◽  
Density Lipoprotein ◽  
Very Low Density Lipoprotein ◽  
Low Density ◽  
Rat Liver Microsomes ◽  
Microsomal Membranes ◽  
Latent Activity

The possibility that triacylglycerol (TAG) synthesis occurs on both aspects of the endoplasmic-reticular membrane during the process of incorporation of TAG into secreted very-low-density lipoprotein (VLDL) [Zammit (1996) Biochem. J. 314, 1-14] was investigated by measuring the latency of diacylglycerol acyltransferase (DGAT) in microsomal fractions obtained from rat liver homogenates. Permeabilization of microsomes with taurocholate resulted in the doubling of the activity, indicating that DGAT activities of approximately equal magnitude occur on either aspect of the microsomal membrane. The taurocholate concentrations required for exposure of the latent activity of DGAT were identical with those that resulted in the exposure of marker enzymes for the lumen of the endoplasmic reticulum. Fractionation of the microsomes into smooth and rough populations indicated that the distribution of overt and latent DGAT activities was the same throughout. The possibility that taurocholate effects may result from non-specific activation of the overt enzyme was excluded by employing the channel-forming peptide alamethicin to effect permeabilization, and by varying the mode of delivery of diacylglycerol substrate to the microsomal membranes. Permeabilization using alamethicin gave a slightly higher latent/overt ratio for DGAT. The possible roles of overt and latent DGAT activities in the synthesis and secretion of TAG by the liver are discussed.

Studies on the Thromboplastic Effect of Human Plasma Lipoproteins

1976 ◽  
Vol 35 (01) ◽  
pp. 178-185 ◽  
Author(s):  
Helena Sandberg ◽  
Lars-Olov Andersson
Keyword(s):  
High Density Lipoprotein ◽  
Human Plasma ◽  
Platelet Rich Plasma ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Plasma Lipoproteins ◽  
Very Low Density Lipoprotein ◽  
Low Density ◽  
Free Plasma ◽  
Good Agreement

SummaryHuman plasma lipoprotein fractions were prepared by flotation in the ultracentrifuge. Addition of these fractions to platelet-rich, platelet-poor and platelet-free plasma affected the partial thromboplastin and Stypven clotting times to various degrees. Addition of high density lipoprotein (HDL) to platelet-poor and platelet-free plasma shortened both the partial thromboplastin and the Stypven time, whereas addition of low density lipoprotein and very low density lipoprotein (LDL + VLDL) fractions only shortened the Stypven time. The additions had little or no effect in platelet-rich plasma.Experiments involving the addition of anti-HDL antibodies to plasmas with different platelet contents and measuring of clotting times produced results that were in good agreement with those noted when lipoprotein was added. The relation between structure and the clot-promoting activity of various phospholipid components is discussed.

Effect of Turmeric and Ginger on Lipid Profile in Male Rats Exposed to Oxidative Stress

2019 ◽  
Vol 10 (01) ◽  
Author(s):  
Eman A. Al-Rekabi ◽  
Dheyaa K. Alomer ◽  
Rana Talib Al-Muswie ◽  
Khalid G. Al-Fartosi
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Drinking Water ◽  
Lipid Profile ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Male Rats ◽  
Control Group ◽  
Very Low Density Lipoprotein ◽  
Low Density

The present study aimed to investigate the effect of turmeric and ginger on lipid profile of male rats exposed to oxidative stress induced by hydrogen peroxide H2O2 at a concentration of 1% given with consumed drinking water to male rats. Methods: 200 mg/kg from turmeric and ginger were used, and the animals were treatment for 30 days. Results: the results showed a significant increase in cholesterol, triglycerides, low density lipoprotein (LDL), very low density lipoprotein (VLDL), whereas it explained a significant decrease in high density lipoprotein (HDL) of male rats exposed to oxidative stress when compared with control group. the results showed a significant decrease in cholesterol, triglycerides, (LDL), (VLDL), whereas it explained a significant increase in (HDL) of rats treated with turmeric and ginger at dose 200 mg/kg when compared with male rats exposed to oxidative stress.

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