Acetylcholinesterase aus dem Gift von Bungarus multicinctus. Reinigung und Eigenschaften/The Acetylcholinesterase of Bungarus multicinctus Venom. Purification and Properties

1979 ◽  
Vol 34 (1-2) ◽  
pp. 27-32 ◽  
Author(s):  
H. Großmann ◽  
M. Weinert ◽  
M. Liefländer

Abstract Acetylcholinesterase from Banded krait (Bungarus multicinctus) venom has been purified by CM-Sephadex chromatography and affinity chromatography to a specific activity of 4290 U/mg. The purified enzyme is a glycoprotein. It is free of electrophoretically detectable contaminating proteins. A molecular weight of 140 000 ± 5 000 has been determined by gradient gel electrophoresis for the native enzyme. It is split into two equal-sized subunits (Mr 70 000 ± 2 000) by SDS treatment. The N-terminal amino acid analysis gave glycine and serine. The purified acetyl­ cholinesterase can be resolved by disc gel electrophoresis into four and by isoelectric focusing into six isozymes. The pI value of the main isozyme has been found to be 5.98 ± 0.05.

1979 ◽  
Vol 34 (9-10) ◽  
pp. 721-725 ◽  
Author(s):  
Heinz Großmann ◽  
Manfred Liefländer

Abstract Acetylcholinesterase was released from bovine erythrocytes by Triton X-100 treatment and pu­rified by twofold affinity chromatography. The detergentfree enzyme was obtained with a specific activity of 4130 U /mg (303 000-fold purification) and a 25% yield. Alternatively, the commercial available crude enzyme was purified. The latter preparation has an uniform molecular weight (Mr 175 000). The Triton-solubilized enzyme, however, can be resolved after removal of the detergent in eight multiple forms (Mr 175 000 and multiple values), in the presence of Triton there exists only one form (Mr 338 000). The amino acid composition of the two enzyme preparations differs significantly. No differences were observed with respect to other properties: SDS gel electrophore­sis revealed two protein bands (Mr 166 000 and 86 000) with both preparations. The enzyme is a glycoprotein with a pI value of 4.3 and contains strongly bound phosphatidylethanolamine. The N-terminal amino acid has been found to be Glu (or Gin).


1975 ◽  
Author(s):  
A.D. Muller ◽  
B. M. Bas ◽  
H. C. Hemker

Staphylocoagulase, an exoprotein of coagulase positive staphylocoagulase, has been purified to a state in which only trace amounts of contaminating proteins are detectable.Purification was more than 35,000 fold, which is 7 times more than the highest value reported in the literature. The yield was about 15%.Aspartic acid was found as a single N-terminal amino acid in this preparation. The molecular weight is 61,000 and the isoelectric point lies at pH 4.53.The amino acid composition was determined.


1983 ◽  
Vol 209 (1) ◽  
pp. 151-157 ◽  
Author(s):  
C J Bailey ◽  
P D Turner

Tryptophan synthase was purified from baker's yeast. The purified enzyme exhibited one band on polyacrylamide-gel electrophoresis, had no detectable N-terminal amino acid and C-terminal alanine. The amino acid composition was close to that predicted by recent studies on the DNA sequence of the structural gene for the enzyme. Kinetic parameters for the following three activities were measured: indole-serine condensation, indolylglycerol phosphate lyase and the overall reaction of serine with 1-(indol-3-yl)glycerol 3-phosphate. The Km for indole was much lower than suggested by previous investigations, and the value of 11 microM was measured by a fluorimetric assay.


1974 ◽  
Vol 143 (3) ◽  
pp. 575-586 ◽  
Author(s):  
Christopher W. Wharton

1. Purified stem bromelain (EC 3.4.22.4) was eluted from Sephadex G-100 as a single peak. The specific activity across the elution peak was approximately constant towards p-nitrophenyl hippurate but increased with elution volume with N2-benzoyl-l-arginine ethyl ester as substrate. 2. The apparent molecular weight, determined by elution analysis on Sephadex G-100, is 22500±1500, an anomalously low value. 3. Purified stem bromelain was eluted from CM-cellulose CM-32 as a single peak and behaved as a single species during column electrophoresis on Sephadex G-100. 4. Purified stem bromelain migrates as a single band during polyacrylamide-gel electrophoresis under a wide variety of conditions. 5. The molecular weight determined by polyacrylamide-gel electrophoresis in the presence of sodium dodecyl sulphate is 28500±1000. 6. Sedimentation-velocity and equilibrium-ultracentrifugation experiments, under a variety of conditions, indicate that bromelain is an apparently homogeneous single peptide chain of mol.wt. 28400±1400. 7. The N-terminal amino acid composition is 0.64±0.04mol of valine and 0.36±0.04mol of alanine per mol of enzyme of mol.wt. 28500. (The amino acid recovery of the cyanate N-terminal amino acid analysis was standardized by inclusion of carbamoyl-norleucine at the cyclization stage.) 8. The pH-dependence of the Michaelis parameters of the bromelain-catalysed hydrolysis of N-benzyloxycarbonyl-l-phenylalanyl-l-serine methyl ester was determined. 9. The magnitude and pH-dependence of the Michaelis parameters have been interpreted in terms of the mechanism of the enzyme. 10. The enzyme is able to bind N-benzyloxycarbonyl-l-phenylalanyl-l-serine methyl ester relatively strongly but seems unable to make use of the binding energy to promote catalysis.


1983 ◽  
Vol 213 (3) ◽  
pp. 617-624 ◽  
Author(s):  
T Nilsson ◽  
I Sjöholm ◽  
B Wiman

The reaction between complement factor C1s and C1-esterase inhibitor has been investigated by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, N-terminal amino acid analysis and c.d. studies. It is confirmed that a very stable stoichiometric 1:1 complex with a molecular weight of about 180000 is formed, involving the light chain of C1s. On the sodium dodecyl sulphate/polyacrylamide gels a small peptide with a molecular weight of about 5000 can be seen, which may be released from the C-terminal portion of the inhibitor moiety in a manner analogous to that occurring in other similar proteinase-inhibitor reactions. By N-terminal amino acid analysis, a newly formed threonine residue is found in the complex, suggesting that the inhibitor peptide chain is cleaved in the complex between C1s and C1-esterase inhibitor. The stabilizing bond may therefore be an ester bond. C.d. studies of the native C1-esterase inhibitor indicated the presence of about 38% alpha-helix, about 24% beta-structure and about 38% unordered structure. By gradual cleavage of the disulphide bridges under non-denaturating conditions, gradual changes in the c.d. spectra occurred, suggesting loss of ordered secondary structures. The c.d. spectra of the complex between C1s and C1-esterase inhibitor indicate that tryptophan residues are affected by the complex-formation.


1973 ◽  
Vol 51 (11) ◽  
pp. 1551-1555 ◽  
Author(s):  
Tony C. M. Seah ◽  
A. R. Bhatti ◽  
J. G. Kaplan

At any stage of growth of a wild-type bakers' yeast, some 20% of the catalatic activity of crude extracts is not precipitable by means of antibody prepared against the typical catalase (catalase T), whose purification and properties have been previously described. Some of this catalatic activity is due to the presence of an atypical catalase (catalase A), a heme protein, with a molecular weight estimated as 170 000 – 190 000, considerably lower than that of the usual catalases (225 000 – 250 000). Preparations of catalase A were found to be homogeneous in the analytical ultracentrifuge and in polyacrylamide gel electrophoresis. Its subunit molecular weight, determined from its iron content, was 46 500, virtually the same as that of the major band obtained in gel electrophoresis in the presence of sodium dodecyl sulfate, suggesting that the native protein is tetrameric. Its specific activity is in the range of those reported for other typical catalases.


1968 ◽  
Vol 23 (11) ◽  
pp. 1412-1426 ◽  
Author(s):  
H. D. Schlumberger

Purification of commercially available HCG preparations with DEAE Sephadex A 50 and Sephadex G 100 column chromatography gave homogeneous fractions having specific biological activities four fold those of the starting materials. The purified HCG has ICSH characteristics and, in high doses, a definite FSH effect is present.Chemical analysis of HCG showed it to contain 29% carbohydrates and 69% peptides. The C-terminal amino acid of the peptide chain was found to be serine, but the N-terminal amino acid could not be determined with normal methods. A molecular weight of 22000 — 27000 daltons was obtained by quantitative end group analysis. Ultracentrifugation experiments in 4 m guanidine hydrochloride gave a molecular weight of 27200 daltons, but in neutral saline solutions at HCG concentrations above 2 mg/ml the apparent molecular weight was higher and indicated dimer formation. A dissociation constant of 10-5 mol/l was estimated for the monomer-dimer equilibrium. Since biological activity is found with 0.1 to 0.5 µg, it was concluded that the HCG monomer is the active entity.The purified HCG is stable from pH 4.5 to pH 10 for 6 hours at 37 °C. At pH 2.5 only 5 to 10% of the original activity is retained. HCG is rapidly inactivated at 100 °C, but a residual activity of 6 — 10% remained after 30 minutes at 80 °C. No activity was lost after 30 minutes incubation at 60 °C.


2001 ◽  
Vol 67 (11) ◽  
pp. 5197-5203 ◽  
Author(s):  
Alexandre Da Costa ◽  
Philippe Michaud ◽  
Emmanuel Petit ◽  
Alain Heyraud ◽  
Philippe Colin-Morel ◽  
...  

ABSTRACT A glucuronan lyase extracted from Sinorhizobium meliloti strain M5N1CS was purified to homogeneity by anion-exchange chromatography. The purified enzyme corresponds to a monomer with a molecular mass of 20 kDa and a pI of 4.9. A specific activity was found only for polyglucuronates leading to the production of 4,5-unsaturated oligoglucuronates. The enzyme activity was optimal at pH 6.5 and 50°C. Zn2+, Cu2+, and Hg2+ (1 mM) inhibited the enzyme activity. No homology of the enzyme N-terminal amino acid sequence was found with any of the previously published protein sequences. This enzyme purified fromS. meliloti strain M5N1CS corresponding to a new lyase was classified as an endopolyglucuronate lyase.


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