scholarly journals Further purification and characterization of the acid α-glucosidase

1968 ◽  
Vol 108 (2) ◽  
pp. 161-167 ◽  
Author(s):  
F. Auricchio ◽  
C. B. Bruni ◽  
V. Sica

1. Centrifugation of rat liver acid glucosidase, which had been purified by adsorption on dextran gel, on a density gradient of sucrose showed the enzyme to be impure. 2. Preliminary purification of the enzyme before the gel filtration improved the final degree of purity of this preparation. Disc gel electrophoresis of this preparation showed a single band of protein. 3. The sedimentation co-efficient and the molecular weight determined on a sucrose gradient were 4·9–5·1s and 76000–83000 respectively for the rat liver enzyme, and 5·6s and 97000 for the acid α-glucosidase purified by means of the same procedure from the human kidney. 4. The Michaelis constants of rat liver and human kidney enzyme were 4·7×10−3m and 13·6×10−3m respectively with maltose as substrate. 5. The enzyme from both tissues was inhibited by tris and by erythritol. The inhibition of the rat liver acid glucosidase by erythritol was competitive.

1998 ◽  
Vol 64 (2) ◽  
pp. 789-792 ◽  
Author(s):  
Giuliano Degrassi ◽  
Benedict C. Okeke ◽  
Carlo V. Bruschi ◽  
Vittorio Venturi

ABSTRACT Bacillus pumilus PS213 was found to be able to release acetate from acetylated xylan. The enzyme catalyzing this reaction has been purified to homogeneity and characterized. The enzyme was secreted, and its production was induced by corncob powder and xylan. Its molecular mass, as determined by gel filtration, is 190 kDa, while sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed a single band of 40 kDa. The isoelectric point was found to be 4.8, and the enzyme activity was optimal at 55°C and pH 8.0. The activity was inhibited by most of the metal ions, while no enhancement was observed. The Michaelis constant (Km ) andV max for α-naphthyl acetate were 1.54 mM and 360 μmol min−1 mg of protein−1, respectively.


1995 ◽  
Vol 308 (3) ◽  
pp. 983-989 ◽  
Author(s):  
I N Fleming ◽  
S J Yeaman

N-Ethylmaleimide-insensitive phosphatidic acid phosphohydrolase (PAP; EC 3.1.3.4) was purified 5900-fold from rat liver. The enzyme was solubilized from membranes with octylglucoside, fractionated with (NH4)2SO4, and purified in the presence of Triton X-100 by chromatography on Sephacryl S300, hydroxyapatite, heparin-Sepharose and Affi-Gel Blue. Silver-stained SDS/PAGE indicated that the enzyme was an 83 kDa polypeptide. Sephacryl S-300 gel filtration also produced a second peak of enzyme activity, which was eluted from all of the chromatography columns at a different position from the purified enzyme. SDS/PAGE indicated that it contained three polypeptides (83 kDa, 54 kDa and 34 kDa), and gel filtration suggested that it was not an aggregate of the purified enzyme. Both forms were sensitive to inhibition by amphiphilic amines, Mn2+ and Zn2+, but not by N-ethylmaleimide. Purified PAP required detergent for activity, but was not activated by Mg2+, fatty acids or phospholipids. The enzyme was able to dephosphorylate lysophosphatidic acid or phosphatidic acid, and was inhibited by diacylglycerol and monoacylglycerol. No evidence was obtained for regulation of PAP by reversible phosphorylation.


1986 ◽  
Vol 234 (2) ◽  
pp. 349-354 ◽  
Author(s):  
S A M Martin ◽  
J O Bishop

Histidine decarboxylase was purified 800-fold from the kidneys of thyroxine-treated mice. The purification procedure included precipitation of protein from a crude supernatant after heating it to 55 degrees C at pH 5.5, fractionation with (NH4)2SO4, phosphocellulose column chromatography, chromatofocusing, DEAE-Sepharose column chromatography, gel filtration on Sephacryl S-300 and preparative polyacrylamide-gel electrophoresis. The native enzyme had an estimated Mr of 113 000. The protein was analysed in SDS/10%-polyacrylamide gels and formed a single band corresponding to a subunit Mr of 55 000, indicating that it is a dimer. Three forms of the enzyme were resolved on isoelectrofocusing gels, with pI 5.3, 5.5 and 5.7.


1979 ◽  
Vol 42 (05) ◽  
pp. 1536-1547
Author(s):  
Hsin Fu Chen ◽  
Masao Nakabayashi ◽  
Kazuo Satoh ◽  
Shoichi Sakamoto

SummaryA new method is described for the preparation of highly purified human plasminogen and plasmin with specific activity of 32 CTA units per mg of protein. With this method, the purification of the urinary plasminogen + plasmin antigenic materials from patients with chronic glomerulonephritis, disseminated intravascular coagulation syndrome and severe toxemia of pregnancy was performed, and the resulting highly purified proenzyme and enzyme were analyzed by immunoelectrophoresis, separative agar electrophoresis, gel filtration and SDS-gel electrophoresis.Our findings indicated that urinary plasmin reflects more closely the extent of intraglomerular fibrinolysis, while urinary plasminogen reflects non-selective proteinuria in patients with chronic glomerulonephritis or severe toxemia of pregnancy.


2001 ◽  
Vol 67 (8) ◽  
pp. 3746-3749 ◽  
Author(s):  
Yu-Huan Liu ◽  
Ying-Cheng Chung ◽  
Ya Xiong

ABSTRACT A dimethoate-degrading enzyme from Aspergillus nigerZHY256 was purified to homogeneity with a specific activity of 227.6 U/mg of protein. The molecular mass of the purified enzyme was estimated to be 66 kDa by gel filtration and 67 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The isoelectric point was found to be 5.4, and the enzyme activity was optimal at 50°C and pH 7.0. The activity was inhibited by most of the metal ions and reagents, while it was induced by Cu2+. The Michaelis constant (K m ) andV max for dimethoate were 1.25 mM and 292 μmol min−1 mg of protein−1, respectively.


1987 ◽  
Vol 248 (1) ◽  
pp. 139-144 ◽  
Author(s):  
E R Sjoberg ◽  
J D Hatton ◽  
J S O'Brien

We describe here the purification and characterization of a form of acid lipase from human liver (designated ALII), which differed from the more abundant Mr-29000 form (ALI). ALII was solubilized from frozen human liver with Triton X-100 and purified 8500-fold by chromatography over concanavalin A-sepharose, CM-cellulose and finally h.p.l.c. over a Mono S column. ALII migrated as a single band on polyacrylamide-gel electrophoresis in both the presence and the absence of SDS. The Mr of ALII was estimated to be 58,500 by SDS/polyacrylamide-gel electrophoresis. Gel filtration on Sephacryl S-200 gave an apparent Mr of 69,000. 4-Methylumbelliferyl (4MU) palmitate, cholesterol oleate and triolein were substrates for ALII, with apparent Vmax values of 5000, 1100 and 2500 nmol/min per mg respectively and Km values of 1.0, 1.5 and 1.8 mM respectively. Cholesterol oleate and triolein were hydrolysed optimally by ALII at pH 4.5, whereas 4MU palmitate was hydrolysed optimally at pH 5.3. Antisera were raised against ALI and ALII and, on immunoblot analysis, no antigenic similarity was observed between ALI and ALII. Cellulose acetate electrophoresis followed by reaction with 4MU palmitate revealed two forms of lipase, corresponding to ALI and ALII. The two enzymes were also separated by hydrophobic chromatography. The activity of ALII was stimulated by several proteins and was partially inhibited by millimolar concentrations of NaCl, CaCl2 and MgSO4.


1975 ◽  
Author(s):  
A. P. Ball ◽  
J. Fenton ◽  
D. L. Aronson ◽  
R. B. Franza ◽  
A. M. Young

Considerable quantities of the non-thrombin portions of human prothrombin (II) have become available as a byproduct of the large-scale production of human thrombin (Biochim. Biophys. Acta 229, 26). Components not adsorbed on CG-50 are further purified by DEAE-cellulose chromatography and gel filtration, yielding the NH2-terminal fragment (F1) and the inner fragment (F2) which are homogeneous by SDS gel electrophoresis. SDS gel electrophoresis of reduced F1 indicates variable amounts of a two-chain derivative, F1’, with one chain migrating just ahead of F1 and one just ahead of the thrombin A-chain. The F1 → F1’ conversion is catalyzed by thrombin with the creation of a new MH2-terminal threonine. Ultracentrifugal patterns of human F1 and F2 closely resemble those of the bovine fragments. NH2-terminal residues were found to be alanine (± threonine) for F1 and serine for F2. Minor deviations from the reported amino acid compositions of bovine F1 and F2 were observed, primarily in the acidic residues. Other properties include:Immunization of rabbits with F1 gave a precipitating antibody to F1 which cross-reacts with II, but native F2 does not appear to be immunogenic. 3H-F1 is rapidly cleared from the blood of rabbits (T 1/2 20 min), with a major portion detectable in the urine.


1979 ◽  
Vol 183 (3) ◽  
pp. 579-588 ◽  
Author(s):  
R D Campbell ◽  
N A Booth ◽  
J E Fothergill

Bovine C1s, a subcomponent of the first component of complement, was purified in good yield by a combination of euglobulin precipitation and ion-exchange and molecular-sieve chromatography. Approx. 10 mg can be obtained from 3 litres of serum, representing a yield of 11%. The C1s is obtained in zymogen form, with a mol.wt. of 85000-88000, determined by gel filtration and SDS/polyacrylamide-gel electrophoresis. It is haemolytically active when tested with human C1q and C1r. Activation can be achieved by incubation with human C1r, resulting in cleavage of the C1s chain into two chains of 65000 and 27000 mol.wt. and the generation of an isoleucine N-terminal residue on the smaller chain. Active C1s binds an equimolar amount of di-isopropyl phosphorfluoridate to the smaller chain, which is the C-terminal part in the zymogen. The chains can be separated by ion-exchange in 8 M-urea. All of these characteristics show that bovine C1s is very similar to its human counterpart.


1990 ◽  
Vol 265 (3) ◽  
pp. 735-738 ◽  
Author(s):  
P J White ◽  
J Young ◽  
I S Hunter ◽  
H G Nimmo ◽  
J R Coggins

The enzyme 3-dehydroquinase was purified over 4000-fold to homogeneity from Streptomyces coelicolor. The subunit Mr estimated from polyacrylamide-gel electrophoresis in the presence of SDS was 16,000. The native Mr estimated by gel filtration on a Superose 6 column was 209,000, indicating that the enzyme is a large oligomer. The enzyme was found to be extremely thermostable. This stability, along with the structural and kinetic properties of the enzyme, suggest that it is very similar to the quinate-inducible 3-dehydroquinase found in Neurospora crassa and Aspergillus nidulans. This similarity was confirmed by direct N-terminal sequencing.


1999 ◽  
Vol 65 (7) ◽  
pp. 2907-2911 ◽  
Author(s):  
Karine Berthelot ◽  
Francis M. Delmotte

ABSTRACT A novel α-glucosidase with an apparent subunit mass of 59 ± 0.5 kDa was purified from protein extracts of Rhizobium sp. strain USDA 4280, a nodulating strain of black locust (Robinia pseudoacacia L), and characterized. After purification to homogeneity (475-fold; yield, 18%) by ammonium sulfate precipitation, cation-exchange chromatography, hydrophobic chromatography, dye chromatography, and gel filtration, this enzyme had a pI of 4.75 ± 0.05. The enzyme activity was optimal at pH 6.0 to 6.5 and 35°C. The activity increased in the presence of NH4 +and K+ ions but was inhibited by Cu2+, Ag+, Hg+, and Fe2+ ions and by various phenyl, phenol, and flavonoid derivatives. Native enzyme activity was revealed by native gel electrophoresis and isoelectrofocusing-polyacrylamide gel electrophoresis with fluorescence detection in which 4-methylumbelliferyl α-glucoside was the fluorogenic substrate. The enzyme was more active with α-glucosides substituted with aromatic aglycones than with oligosaccharides. This α-glucosidase exhibited Michaelis-Menten kinetics with 4-methylumbelliferyl α-d-glucopyranoside (Km , 0.141 μM; V max, 6.79 μmol min−1 mg−1) and withp-nitrophenyl α-d-glucopyranoside (Km , 0.037 μM; V max, 2.92 μmol min−1 mg−1). Maltose, trehalose, and sucrose were also hydrolyzed by this enzyme.


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