Search results for "molecular mass"
showing 10 items of 155 documents
Purification and characterization of the ?-β-hydroxybutyrate dehydrogenase from dromedary liver mitochondria
2001
Abstract d -β-Hydroxybutyrate dehydrogenase (BDH) (EC 1.1.1.30), a membrane enzyme, has been purified to homogeneity from dromedary ( Camelus dromedarius ) liver mitochondria. Our new purification method consisted of the solubilization of mitochondrial membranes by Triton X 100 and purification of BDH by two steps: DEAE-Sephacel and Phenyl-Sepharose. The molecular mass of the enzyme subunit size was 67 kDa. The purified enzyme is recognized by anti rat liver mitochondrial BDH antibodies. Furthermore, BDH activity was absolutely dependent upon phospholipids. BDH is also characterized by specific enzymatic parameters: an optimum pH of approximately 8 for the oxidation reaction, and approximat…
Marine tumor vaccine carriers: structure of the molluscan hemocyanins KLH and htH.
2002
Keyhole limpet hemocyanin (KLH) is a well-established immune stimulant and hapten carrier, and Haliotis tuberculata hemocyanin (HtH) is a related product. Biologically, KLH and HtH are blue copper proteins which serve as oxygen carriers in the blood of the keyhole limpet Megathura crenulata and the abalone H. tuberculata, respectively, two marine gastropods. Both hemocyanins occur as two distinct isoforms, termed KLH1 KLH2, HtH1, and HtH2. Each of these molecules is based on a very large polypeptide chain, the subunit (molecular mass ca 400 kDa), which is folded into a series of eight globular functional units (molecular mass ca 50 kDa each). Twenty copies of this subunit form a cylindrical…
Purification and characterization of two exopolyphosphatases from the marine sponge Tethya lyncurium
1995
Abstract Two exopolyphosphatases (exopolyphosphatase I and II; EC 3.6.1.11) which release orthophosphate from inorganic polyphosphates have been detected and purified for the first time from a marine sponge, Tethya lyncurium . Exopolyphosphatase I has a molecular mass of 45 kDa, a pH optimum of 5.0 and does not require divalent cations for activity, while exopolyphosphatase II has a molecular mass of 70 kDa, a pH optimum of 7.5 and displays optimal activity in the presence of Mg 2+ ions. Final purification of the enzymes could be achieved by affinity chromatography on polyphosphate-modified zirconia. The mode of action of both enzymes was found to be processive. Orthophosphate is the sole p…
Purification and characterization of a pore-forming protein from the marine sponge Tethya lyncurium
1992
A pore-forming protein was detected and purified for the first time from a marine sponge (Tethya lyncurium). The purified protein has a polypeptide molecular mass of 21 kDa and a pI of 6.4. Tethya pore-forming protein (also called Tethya hemolysin) rapidly lysed erythrocytes from a variety of organisms. After binding to target membranes, the hemolysin resisted elution with EDTA, salt or solutions of low ionic strength and hence resembled an integral membrane protein. Erythrocytes could be protected from hemolysis induced by Tethya hemolysin by addition of 30 mM dextran 4 (4-6 kDa; equivalent hydrodynamic diffusion radius, 1.75-2.3 nm) to the extracellular medium, but not by addition of unch…
Chemical and catalytical properties of thermal polymers of amino acids (proteinoids)
1974
The significance of thermal polyamino acids (proteinoids) as abiotic predecessors of proteins is reviewed on the basis of new experimental results. Most proteinoids yield only 50% to 80% amino acid upon acid hydrolysis. They contain 40% to 60% less peptide links than typical proteins, whereas their average nitrogen content is like that of proteins. The arrangement of amino acid residues is nonrandom. The degree of nonrandomness is difficult to determine because unusual crosslinks disturb most of the sequencing methods typically applied in protein chemistry. The products obtained in a polymerization experiment are heterogeneous. They can be separated into a limited number of related fraction…
Silica Entrapment for Significantly Stabilized, Energy-Conducting Light-Harvesting Complex (LHCII)
2014
The major light-harvesting chlorophyll a/b complex (LHCII) of the photosynthetic apparatus in green plants consists of a membrane protein and numerous noncovalently bound pigments that make up about one-third of the molecular mass of the pigment-protein complex. Due to this high pigment density, LHCII is potentially interesting as a light-harvesting component in synthetic constructs. However, for such applications its stability needs to be significantly improved. In this work, LHCII was dramatically stabilized by enclosing it within polymerizing colloidal silica. The entrapped LHCII stayed functional at 50 °C for up to 24 h instead of a few minutes in detergent solution and clearly showed e…
Die Elimination von Hydroxyäthylstärke 200/0,5, Dextran 40 und Oxypolygelatine
1982
After withdrawal of 400 ml whole blood and subsequent infusion of 500 ml of a colloidal plasma substituent, the intravascular and renal colloid elimination was investigated in 40 test subjects. The individual colloidal solutions could no longer be demonstrated in the intravascular space after the following times: 10% hydroxyethyl starch 200/0.5 (anthrone method) after six weeks, 10% dextran 40 (anthrone method) after two weeks, 6% hydroxyethyl starch 200/0.5 (anthrone method) after four weeks and 5.5% oxypolygelatine (hydroxyproline method) after two days. Colloidal plasma substitutes are polydisperse solutions with various molecular weights and degree of hydroxyethylation and therefore, al…
Isolation and partial characterization of uronic acid-containing glycoproteins from Mucor rouxii.
1995
Five different fractions containing uronic acids associated with protein were isolated from the cytoplasm of the filamentous form of Mucor rouxii. A signle fraction was isolated from the cell wall by hot sodium dodecyl sulfate followed by ion exchange column chromatography. Two cytoplasmic entities (peaks I and II) were not adsorbed to DEAE Bio-Gel A. The molecular mass of peaks I to V ranged from 16.5 to 210 kDa. The protein-uronic acid ratios were different for each fraction. The cell wall fraction showed a molecular mass of 16.5 kDa, similar to that of peak II but with differences in chromatographic behavior and protein-uronic acid ratio. The possible role of these molecules as acceptors…
Membrane Protein Subunit Fractionation by Means of Inverse Pore Gradient Elution Polyacrylamide Gel Electrophoresis
1996
We report here the preparative scale isolation of the four subunits of the nicotinic acetylcholine receptor (nAChR) applying short inverse pore gradient SDS gels on an elution-PAGE apparatus. The nAChR subunits are of similar molecular weights (alpha, 50.2 kDa; beta, 53.7 kDa; gamma, 56.3 kDa; delta, 57.6 kDa) and isoelectric point (approx 5.5) and share the typical properties of amphiphatic membrane proteins that are difficult to separate by chromatographic procedures. Preparative PAGE, which has proved to be the method of choice for nAChR-subunit fractionation, however, is time-consuming and achieves only moderate resolutions yielding dilute fractions. We present here the fractionation of…
Purification and Characterization of <I>Bacillus cereus</I> Protease Suitable for Detergent Industry
2005
An extracellular alkaline protease from an alkalophilic bacterium, Bacillus cereus, was produced in a large amount by the method of extractive fermentation. The protease is thermostable, pH tolerant, and compatible with commercial laundry detergents. The protease purified and characterized in this study was found to be superior to endogenous protease already present in commercial laundry detergents. The enzyme was purified to homogeneity by ammonium sulfate precipitation, concentration by ultrafiltration, anion-exchange chromatography, and gel filtration. The purified enzyme had a specific activity of 3256.05 U/mg and was found to be a monomeric protein with a molecular mass of 28 and 31 kD…