Distribution of lipoprotein lipase and hepatic lipase between plasma and tissues: effect of hypertriglyceridemia

Peterson, Jonas; Olivecrona, Thomas; Bengtsson‐Olivecrona, Gunilla

doi:10.1016/0005-2760(85)90049-9

Cited by 118 publications

(69 citation statements)

References 41 publications

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“…After preincubation for 10 min at room temperature, LPL was added. The reaction was stopped after another 10min and the released fatty acids were extracted and radioactivity measured as previously described (Peterson et al, 1985).…”

Section: Enzyme Assaysmentioning

confidence: 99%

Chymotryptic cleavage of lipoprotein lipase

Lóokene

Bengtsson‐Olivecrona

1993

European Journal of Biochemistry

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Treatment of bovine lipoprotein lipase (LPL) with chymotrypsin results in cleavage between residues Phe390-Ser391 and between Trp392-Sa393, indicating that this region is exposed in the native conformation of LPL. Two main fragments are generated, one large including the aminoterminus (chymotrypsin-truncated LPL = c-LPL) and one small, carboxy-terminal fragment. The small fragment is not stable, but is further degraded by the protease. Isolated c-LPL has full catalytic activity against tributyryl glycerol (tributyrin) and p-nitrophenyl butyrate, while the activity against emulsions of long-chain triacylglycerols and against liposomes is reduced and the activity against milk fat globules and chylomicrons is lost. Several. properties of c-LPL were investigated. It was found that c-LPL interacts with apolipoprotein CII (apo CII) as efficiently as intact LPL. The truncated enzyme bound to liposomes and to emulsions of long-chain triacylglycerols as well as the intact enzyme did. In contrast, c-LPL did not bind to milk fat globules or to chylomicrons. The activity of c-LPL was more sensitive to inhibition by other lipid-binding proteins, e.g. apolipoprotein CIII (apo CIII), than was the intact enzyme. The affinity for heparin was as high with c-LPL as with intact LPL. Like intact LPL, c-LPL is dimeric in its active form, as evidenced by sucrose density gradient centrifugation.It is concluded that the reduced catalytic and lipid-binding properties of c-LPL compared with intact LPL are related to the properties of the substrate interface. It is speculated that the carboxyterminal part of LPL contains a secondary lipid-binding site, which is important for activity against chylomicrons and related substrates.

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Section: Enzyme Assaysmentioning

confidence: 99%

Chymotryptic cleavage of lipoprotein lipase

Lóokene

Bengtsson‐Olivecrona

1993

European Journal of Biochemistry

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“…For assay of activators for lipoprotein lipase in column fractions and in slices of polyacrylamide gels, an incubation mixture with 3H-labeled triolein sonicated into IntralipidR as described by Peterson et al [47] was used. Serum was omitted from the incubation mixture which was otherwise as described.…”

Section: Methodsmentioning

confidence: 99%

“…The mixtures were preincubated with activator for at least 5 min at 25°C before addition of a standard amount of lipoprotein lipase. Fatty acids were extracted and counted as described [47]. 1 U lipase activity corresponds to 1 pmol fatty acid released/min at 25 "C.…”

Section: Methodsmentioning

confidence: 99%

Primary structure of the bovine analogues to human apolipoproteins CII and CIII

Bengtsson‐Olivecrona

Sletten

1990

European Journal of Biochemistry

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Two major isoforms of the bovine analogue to human apolipoprotein (apo) CII were purified from plasma. They were both as effective as human apo CII in activating lipoprotein lipase. Amino acid sequencing revealed that one form contained 79 amino acid residues, and corresponded to human pro apo CII. The other form lacked the first six residues at its N-terminus. This was apparently due to cleavage of the -Gln-Asp-linkage in the sequence H2N-Ala-His-Val-Pro-Gln-Gln-Asp-Glu-, analogous to cleavages described for human apo A1 and apo CII.Previous studies with human apo CII have shown that the ability to activate lipoprotein lipase resides in the C-terminal third of the molecule. This was highly conserved in the bovine analogue: of the 30 last residues, 21 are identical. Five residues in this part of human apo CII have been reported to be essential for activation of lipoprotein lipase. Only one of these, Tyr63, is present in the bovine sequence. The bovine structure contains a threonine at position 61, instead of serine in the human, and the four last residues are -Ser-Gly-Lys-Asp instead of the allegedly necessary -Lys-Gly-Glu-Glu. Three differently sialylated isoforms of the bovine analogue to human apolipoprotein CIII were also isolated and partially sequenced. All three lacked the first three N-terminal residues as compared to sequences from other species (man, dog and rat). Sequence differences were more pronounced at the ends than in the central parts of the apo CIII molecules.Transport of triacylglycerol in lipoproteins is a major pathway for energy transfer between tissues. Triacylglycerol-rich lipoproteins are formed in the intestine (chylomicra) and in the liver (very-low-density-lipoproteins). Their metabolism involves two major steps. Most of the triacylglycerols are unloaded by lipoprotein lipase at the vascular endothelium in peripheral tissues [ 11. The resulting remnant lipoproteins are then removed from the circulation mainly by the liver [2 -41. Apolipoproteins (apo) CII and CHI appear to be involved in the regulation of both steps. These proteins have flexible conformations [5] that allow them to bind reversibly to lipid/ water interfaces and to transfer rapidly between lipoprotein particles. When triacylglycerol-rich lipoproteins enter plasma they take up apo CII and CHI; when the particles are degraded by lipoprotein lipase the C apolipoproteins transfer back to other lipoproteins [6, 71. For hydrolysis by lipoprotein lipase the lipoproteins must carry apo CII, an activator for the enzyme [8, 91. In the absence of apo CII, triacylglycerol transport is severely impeded and gross hypertriglyceridemia ensues [lo]. Apo CIII has been shown to impede the interaction of lipoproteins with the remnant receptor, thus preventing their uptake by the liver until the lipase reaction has reduced them sufficiently in size so that most of the C apoproteins have been shed from the particles [4,11, 121. In addition, apo CIII has been shown to inhibit the action of lipoprotein lipase and the Human apo CII is a 79-a...

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“…A standardized oral fat tolerance test was performed in two patients as described indetail previously (Patsch et al, 1983). Lipoprotein lipase and hepatic lipase activities were measured at 25"C in post-heparin plasma using specific antisera (Peterson et al 1985); mean +/-1SD in 50 healthy probands was 287+/-71 and 604+/-139 nmol NEFA.ml -~. min-,, respectively.…”

Section: $48mentioning

confidence: 99%

Long-term follow-up of glycaemic control and parameters of lipid transport after pancreas transplantation

Drexel¹,

Pálos²,

Königsrainer³

et al. 1991

Diabetologia

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Summary. We report the long-term metabolic observations made on 37 patients after simultaneous pancreas and kidney transplantation. Plasma C-peptide levels were above the physiological range in all patients and there was no significant difference between patients undergoing delayed duct occlusion (n=12) or those with drainage of exocrine secretion into the urinary bladder (n=25). HbA 1,, was equally at the upper end of the normal range in both subsets of patients. Mean fasting cholesterol (237 mg/dl) and triglycerides (122 mg/dl) were normal, and HDL-cholesterol was above normal with an average concentration of 77 mg/dl. Two patients underwent an oral fat tolerance test and showed extremely low postprandial lipaemia and very high lipoprotein lipase activities. We conclude that patients with a functioning pancreas graft persistently demonstrate normoglycaemia, elevated Cpeptide, and a very favourable lipid profile both in the fasting and the postprandial state.

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Distribution of lipoprotein lipase and hepatic lipase between plasma and tissues: effect of hypertriglyceridemia

Cited by 118 publications

References 41 publications

Chymotryptic cleavage of lipoprotein lipase

Chymotryptic cleavage of lipoprotein lipase

Primary structure of the bovine analogues to human apolipoproteins CII and CIII

Long-term follow-up of glycaemic control and parameters of lipid transport after pancreas transplantation

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