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1.
S Afr Med J ; 112(6): 426-432, 2022 05 31.
Article in English | MEDLINE | ID: mdl-36217872

ABSTRACT

BACKGROUND: Inclisiran significantly reduced low-density lipoprotein cholesterol (LDL-C) in individuals with heterozygous familial hypercholesterolaemia, established atherosclerotic cardiovascular disease (ASCVD) or ASCVD risk equivalents (type 2 diabetes, familial hypercholesterolaemia or a 10-year risk of a cardiovascular event ≥20%) in the ORION phase III clinical trials. Infrequent dosing at days 1, 90, 270 and 450 resulted in a mean LDL-C reduction of ~50%. A total of 298 participants from South Africa (SA) were enrolled. Local data are needed to support the use of inclisiran in the SA population, potentially addressing an unmet need for additional LDL-C-lowering therapies. Objectives. To analyse the ORION phase III trial data to assess the efficacy and safety of inclisiran in SA participants. Methods. ORION-9, 10 and 11 were randomised, double-blind, phase III trials. Participants were receiving maximally tolerated statins with or without other lipid-lowering therapies (excluding protein convertase subtilisin/kexin type 9 (PCSK9) inhibitors). Participants were randomised 1:1 to inclisiran sodium 300 mg/284 mg (free acid) or placebo administered at days 1, 90, 270 and 450. The co-primary endpoints were the LDL-C percentage change from baseline to day 510 and the time-averaged percentage change in LDL-C from baseline after day 90 up to day 540. Key secondary endpoints included the absolute change in LDL-C from baseline to day 510, the time-averaged absolute change from baseline after day 90 up to day 540, and changes in other lipids and lipoproteins. Results. The mean age of the participants was 58.6 years (56% male). The mean LDL-C level at baseline was 3.6 mmol/L. At day 510, inclisiran reduced LDL-C levels by 54.2% compared with placebo (95% confidence interval (CI) -61.3 - -47.2; p<0.0001). The corresponding time-averaged reduction in LDL-C was 52.8% (95% CI -57.9 - -47.8; p<0.0001). Treatment-emergent adverse events at the injection site were more common with inclisiran compared with placebo (10.1% v. 0.7%); however, all were mild or moderate in nature and none were persistent. Conclusion. Inclisiran, given in addition to maximally tolerated standard lipid-lowering therapy, is effective and safe and results in robust reductions in LDL-C in SA patients at high cardiovascular risk.


Subject(s)
Atherosclerosis , Cardiovascular Diseases , Diabetes Mellitus, Type 2 , Hydroxymethylglutaryl-CoA Reductase Inhibitors , Hyperlipoproteinemia Type II , Cardiovascular Diseases/drug therapy , Cardiovascular Diseases/prevention & control , Cholesterol, LDL , Diabetes Mellitus, Type 2/drug therapy , Female , Heart Disease Risk Factors , Humans , Hyperlipoproteinemia Type II/drug therapy , Male , Middle Aged , Proprotein Convertase 9/therapeutic use , RNA, Small Interfering , Risk Factors , Sodium/therapeutic use , South Africa , Subtilisins/therapeutic use , Treatment Outcome
2.
Enzyme Microb Technol ; 28(7-8): 705-712, 2001 May 07.
Article in English | MEDLINE | ID: mdl-11339956

ABSTRACT

The gene coding for an extracellular lipase of Bacillus licheniformis was cloned using PCR techniques. The sequence corresponding to the mature lipase was subcloned into the pET 20b(+) expression vector to construct a recombinant lipase protein containing 6 histidine residues at the C-terminal. High-level expression of the lipase by Escherichia coli cells harbouring the lipase gene-containing expression vector was observed upon induction with IPTG at 30 degrees C. A one step purification of the recombinant lipase was achieved with Ni-NTA resin. The specific activity of the purified enzyme was 130 units/mg with p-nitrophenyl-palmitate as substrate. The enzyme showed maximum activity at pH 10-11.5 and was remarkably stable at alkaline pH values up to 12. The enzyme was active toward p-nitrophenyl esters of short to long chains fatty acids but with a marked preference for esters with C(6) and C(8) acyl groups. The amino acid sequence of the lipase shows striking similarities to lipases from Bacillus subtilis and Bacillus pumilus. Based on the amino acid identity and biochemical characteristics, we propose that Bacillus lipases be classified into two distinct subfamilies of their own.

3.
Biotechnol Prog ; 15(2): 196-200, 1999.
Article in English | MEDLINE | ID: mdl-10194394

ABSTRACT

Both beta-xylanase and beta-xylosidase were purified to homogeneity from a xylose-grown culture of Aureobasidium pullulans. Cellular distribution studies of enzyme activities revealed that beta-xylanase was an extracellular enzyme, during both the exponential and stationary phases, whereas beta-xylosidase was mostly periplasmic associated. The beta-xylanase exhibited very high specificity for xylan extracted from Eucalyptus grandis dissolving pulp, whereas the beta-xylosidase was only active on p-nitrophenyl xyloside and xylobiose. Comparison of kcat/Km ratios showed that the beta-xylanase hydrolyzed xylan from dissolving pulp 1.3, 2.1, and 2. 3 times more efficiently than Eucalyptus hemicellulose B, Eucalyptus hemicellulose A, and larchwood xylan, respectively. The beta-xylosidase exhibited a transxylosylation reaction during the hydrolysis of xylobiose. When applied on acid sulfite pulp, both enzymes released xylose and hydrolyzed xylan to a different extent. Although beta-xylosidase (0.4 U/g pulp) liberated more xylose from pulp than beta-xylanase (4.7 U/g pulp), it was responsible for only 3% of xylan solubilization. Treatment of pulp with beta-xylanase liberated 51.7 microgram of xylose/g and hydrolyzed 10% of xylan. The two enzymes acted additively on pulp and removed 12% of pulp xylan. A synergistic effect in terms of release of xylose from pulp was observed when the enzyme mixture of beta-xylanase and beta-xylosidase was supplemented with beta-mannanase. However, this did not result in further enzymatic degradation of pulp xylan. Both beta-xylanase and beta-xylosidase altered the carbohydrate composition of sulfite pulp by increasing the relative cellulose content at the expense of reduced hemicellulose content of pulp.


Subject(s)
Carbohydrates/chemistry , Mitosporic Fungi/enzymology , Xylosidases/isolation & purification , Xylosidases/metabolism , Carbohydrate Metabolism , Endo-1,4-beta Xylanases , Hydrolysis , Industry , Kinetics , Paper , Substrate Specificity , Sulfites
4.
Appl Environ Microbiol ; 61(4): 1580-5, 1995 Apr.
Article in English | MEDLINE | ID: mdl-7747971

ABSTRACT

A cytosolic aldo-keto reductase was purified from Saccharomyces cerevisiae ATCC 26602 to homogeneity by affinity chromatography, chromatofocusing, and hydroxylapatite chromatography. The relative molecular weights of the aldo-keto reductase as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and size exclusion chromatography were 36,800 and 35,000, respectively, indicating that the enzyme is monomeric. Amino acid composition and N-terminal sequence analysis revealed that the enzyme is closely related to the aldose reductases of xylose-fermenting yeasts and mammalian tissues. The enzyme was apparently immunologically unrelated to the aldose reductases of other xylose-fermenting yeasts. The aldo-keto reductase is NADPH specific and catalyzes the reduction of a variety of aldehydes. The best substrate for the enzyme is the aromatic aldehyde p-nitrobenzaldehyde (Km = 46 microM; kcat/Km = 52,100 s-1 M-1), whereas among the aldoses, DL-glyceraldehyde was the preferred substrate (Km = 1.44 mM; kcat/Km = 1,790 s-1 M-1). The enzyme failed to catalyze the reduction of menadione and p-benzoquinone, substrates for carbonyl reductase. The enzyme was inhibited only slightly by 2 mM sodium valproate and was activated by pyridoxal 5'-phosphate. The optimum pH of the enzyme is 5. These data indicate that the S. cerevisiae aldo-keto reductase is a monomeric NADPH-specific reductase with strong similarities to the aldose reductases.


Subject(s)
Alcohol Oxidoreductases/isolation & purification , Saccharomyces cerevisiae/enzymology , Alcohol Oxidoreductases/genetics , Alcohol Oxidoreductases/metabolism , Aldehyde Reductase , Aldo-Keto Reductases , Amino Acid Sequence , Animals , Humans , Immunochemistry , Kinetics , Molecular Sequence Data , Molecular Weight , Saccharomyces cerevisiae/genetics , Sequence Homology, Amino Acid , Substrate Specificity
5.
FEBS Lett ; 308(2): 130-2, 1992 Aug 17.
Article in English | MEDLINE | ID: mdl-1499720

ABSTRACT

The NAD-dependent glycerol-3-phosphate dehydrogenase (glycerol-3-phosphate:NAD+ oxidoreductase; EC 1.1.1.8; G3P DHG) was purified 178-fold to homogeneity from Saccharomyces cerevisiae strain H44-3D by affinity- and ion-exchange chromatography. SDS-PAGE indicated that the enzyme had a molecular mass of approximately 42,000 (+/- 1,000) whereas a molecular mass of 68,000 was observed using gel filtration, implying that the enzyme may exist as a dimer. The pH optimum for the reduction of dihydroxyacetone phosphate (DHAP) was 7.6 and the enzyme had a pI of 7.4. NADPH will not substitute for NADH as coenzyme in the reduction of DHAP. The oxidation of glycerol-3-phosphate (G3P) occurs at 3% of the rate of DHAP reduction at pH 7.0. Apparent Km values obtained were 0.023 and 0.54 mM for NADH and DHAP, respectively. NAD, fructose-1,6-bisphosphate (FBP), ATP and ADP inhibited G3P DHG activity. Ki values obtained for NAD with NADH as variable substrate and FBP with DHAP as variable substrate were 0.93 and 4.8 mM, respectively.


Subject(s)
Glycerolphosphate Dehydrogenase/isolation & purification , Saccharomyces cerevisiae/enzymology , Blotting, Western , Chromatography, Affinity , Chromatography, Ion Exchange , Dihydroxyacetone Phosphate/chemistry , Electrophoresis, Polyacrylamide Gel , Enzyme Stability , Glycerolphosphate Dehydrogenase/metabolism , Kinetics , NAD/metabolism , NADP/metabolism , Oxidation-Reduction
6.
Int J Biochem ; 21(6): 695-700, 1989.
Article in English | MEDLINE | ID: mdl-2551754

ABSTRACT

1. Fructose 1,6-bisphosphatase was assayed in crude extracts of physiologically important organs and tissues in the ostrich. 2. Highest activity was found in liver and lowest in brain tissue. 3. No activity was detected in the heart, gizzard or adrenals. 4. The enzyme was purified in homogeneous, apparently undegraded form from liver utilizing Blue dextran-Sepharose affinity chromatography. 5. The enzyme is similar to mammalian fructose 1,6-bisphosphatase in many respects including its indispensability of Mg2+ for catalytic activity. 6. Relative molecular weight of the native enzyme and its subunit is about 150,000 and 35,000 respectively. 7. The amino acid composition of ostrich liver fructose 1,6-bisphosphatase is distinctly different from that of the chicken muscle enzyme, but compares favourably with the composition of the rabbit liver enzyme. 8. The purified enzyme is devoid of tryptophan.


Subject(s)
Birds/metabolism , Fructose-Bisphosphatase/metabolism , Isoenzymes/metabolism , Liver/enzymology , Adrenal Glands/enzymology , Amino Acids/analysis , Animals , Brain/enzymology , Electrophoresis, Polyacrylamide Gel , Fructose-Bisphosphatase/isolation & purification , Gizzard, Avian/enzymology , Isoenzymes/isolation & purification , Molecular Weight , Myocardium/enzymology , Organ Specificity , Substrate Specificity
7.
Biochim Biophys Acta ; 831(2): 186-91, 1985 Oct 04.
Article in English | MEDLINE | ID: mdl-2994743

ABSTRACT

Fructose bisphosphatase (D-fructose-1,6-bisphosphate 1-phosphohydrolase, EC 3.1.3.11) has been isolated in homogeneous form from rat muscle by a simple and convenient procedure, including adsorption on carboxymethylcellulose and substrate elution. The resultant enzyme preparation has a specific activity comparable to that of the enzymes isolated from rabbit liver, rabbit muscle and rat liver. The native relative molecular mass of the enzyme was estimated by sedimentation equilibrium centrifugation to be approx. 138 000, and the enzyme appears to be a tetramer containing subunits of Mr approx. 34 500. The amino acid composition is distinctly different from that of the rabbit muscle, rabbit liver and rat liver enzymes. The purified enzyme contains no tryptophan and has a blocked amino terminal.


Subject(s)
Fructose-Bisphosphatase/isolation & purification , Muscles/enzymology , Amino Acids/analysis , Animals , Chemical Phenomena , Chemistry , Chromatography, Gel , Electrophoresis, Polyacrylamide Gel , Male , Rats , Ultracentrifugation
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