scholarly journals Characterization of human liver α-D-mannosidase purified by affinity chromatography

1976 ◽  
Vol 153 (3) ◽  
pp. 579-587 ◽  
Author(s):  
N C Phillips ◽  
D Robinson ◽  
B G Winchester

Human liver acidic α-D-mannosidase was purified 1400-fold by a relatively short procedure incorporating chromatography on concanavalin A-Sepharose and affinity chromatography on Sepharose 4B-epsilon-aminohexanoylmannosylamine. In contrast with the acidic enzymic activity the neutral α-mannosidase did not bind to the concanavalin A-Sepharose so the two types of α-mannosidase could be separated at an early stage in the purification. The only significant glycosidase contaminant after affinity chromatography on the mannosylamine ligand was α-L-fucosidase, which was selectively removed by affinity chromatography on the corresponding fucosylamine ligand. The final preparation was free of other glycosidase activities. The pI of the purified enzyme was increased from 6.0 to 6.45 on treatment with neuraminidase. Although the pI and the mol.wt. (220 000) suggested that α-mannosidase A had been purified selectively, ion-exchange chromatography on DEAE-cellulose indicated that the preparation consisted predominantly of α-mannosidase B. This discrepancy is discussed in relation to the basis of the multiple forms of human α-mannosidase. The purified enzyme completely removed the α-linked non-reducing terminal mannose from a trisaccharide isolated from the urine of a patient with mannosidosis. A comparison of the activity of the pure enzyme towards the natural substrate and synthetic substrates suggests that the same enzymic activity is responsible for hydrolysing all the substrates. These results validate the use of synthetic substrates for determining the mannosidosis genotype. They are also further evidence that mannosidosis is a lysosomal storage disease resulting from a deficiency of acidic α-mannosidase.

1986 ◽  
Vol 234 (1) ◽  
pp. 157-162 ◽  
Author(s):  
N N Dewji ◽  
D R De-Keyzer ◽  
J L Stirling

beta-N-Acetylhexosaminidase I2 was purified from human liver by a combination of concanavalin A chromatography, DEAE-cellulose chromatography, gel filtration and affinity chromatography on 2-acetamido-N-(6-aminohexanoyl)-2-deoxy-beta-D-glucopyranosylamine coupled to CNBr-activated Sepharose 4B. Its specific activity was 130 mumol/min per mg of protein compared with values of 150 and 320 mumol/min/mg of protein for beta-N-acetylhexosaminidases A and B purified from the same tissue. Km values for I2, A and B were 1.0 mM, 0.8 mM and 0.74 mM respectively. On gradient gel electrophoresis under non-denaturing conditions, hexosaminidase I2 behaved similarly to A and appeared to have an Mr between 100 000 and 110 000. beta-N-Acetylhexosaminidase I2 was resolved into two major polypeptides, of Mr 56 000 and 29 000, on SDS/polyacrylamide-gel electrophoresis under denaturing conditions. Immunoblotting with anti-(hexosaminidase alpha-subunit) serum confirmed that the 56 000-Mr component was the alpha-subunit and anti-(hexosaminidase B) serum reacted with the 29 000 Mr component. beta-N-Acetylhexosaminidase I2 more closely resembles form A than B, but the features of its structure that allow it to be separated from A on the basis of net charge have not yet been found.


1977 ◽  
Vol 163 (2) ◽  
pp. 269-277 ◽  
Author(s):  
N C Phillips ◽  
B G Winchester ◽  
R D Jolly

Antiserum was raised in a rabbit against bovine kidney acidic alpha-mannosidase that had been purified 570-fold by affinity chromatography on concanavalin A--Sepharose and Sepharose 4B-xi-aminohexanoylmannosylamine. The antiserum precipitated the acidic but not the neutral alpha-mannosidase in normal calf tissues. Human acidic alpha-mannosidase cross-reacted partially with the antiserum, emphasizing the close structural resemblance between the enzyme in the two species. The residual acidic alpha-mannosidase in the tissues of a calf with mannosidosis was also precipitated by the antiserum, the same volume of antiserum being required to precipitate a unit of alpha-mannosidase activity from the normal and pathological tissues. The concentration of cross-reacting material detected by antibody-consumption experiments in the organs of the calf with mannosidosis appeared to be proportional to the concentration of the residual acidic alpha-mannosidase. It is suggested that the residual acidic alpha-mannosidase in mannosidosis accounts for the cross-reacting material detected and that it is unlikely that enzymically inactive but cross-reacting material is present. The residual acidic alpha-mannosidase could be a decreased concentration of the normal gene product or an altered enzyme with a decreased specific enzymic activity and a correspondingly decreased antigenicity.


1983 ◽  
Vol 215 (3) ◽  
pp. 605-612 ◽  
Author(s):  
C L Lee ◽  
S S L Li ◽  
C Y Li ◽  
T M Chu

Four ribonucleases (RNAases I-IV) have been purified to homogeneity from human seminal plasma by precipitation with 40-75%-satd. (NH4)2SO4, followed by chromatographies on concanavalin A-Sepharose 4B, DEAE-cellulose phosphocellulose, agarose-5′-(4-aminophenylphospho)uridine 2′(3′)-phosphate (RNAase affinity column) and Sephadex G-75 or G-100. The homogeneity of these RNAases was confirmed by polyacrylamide-gel electrophoresis. Mr values for these purified RNAases were 78 000, 16 000, 13 300 and 5000 as estimated by gel filtration. Enzyme activities of RNAases I, III and IV were inhibited by Mn2+, Zn2+ and Cu2+ and activated by Na+, K+, Ba2+, Mg2+, Fe2+ and EDTA, whereas that of RNAase II was inhibited by Ba2+, Mg2+, Fe2+, Mn2+, Zn2+ and Cu2+ and activated by Na+, K+ and EDTA. RNAases I, II and IV demonstrated a higher affinity for poly(C) and poly(U) or yeast RNA, whereas RNAase III preferentially hydrolysed poly(U) over poly(C) and yeast RNA. In the presence of 5 mM-spermine, RNAase I was dissociated to a low-Mr (5000) enzyme with an increase in total RNAase enzymic activity. Xenoantiserum to each RNAase was raised and evaluated by immunoprecipitation and immunohistochemical methods. Anti-(seminal RNAase III) antiserum showed no immunological cross-reaction with RNAases of other human origin, whereas anti-(seminal RNAase I), -(RNAase II) and -(RNAase IV) antisera exhibited indistinguishable immunological reactions with serum RNAase and other human RNAases, except that anti-(seminal RNAase I) and -(RNAase antisera IV) did not react with pancreatic RNAases. Seminal RNAases I and IV were identical immunologically as shown by anti-(RNAase I) and anti-(RNAase IV) in immunodiffusion. Immunohistochemical study revealed that, among human tissues examined, only prostate expressed seminal RNAase III. These results suggested that human seminal RNAase I may be an aggregated molecule of RNAase IV and that seminal RNAases II and IV are similar to serum RNAases, whereas seminal RNAase III is a prostate-specific enzyme.


2011 ◽  
Vol 63 (3) ◽  
pp. 747-756 ◽  
Author(s):  
A.K.M. Asaduzzaman ◽  
Habibur Rahman ◽  
Tanzima Yeasmin

An acid phosphatase has been isolated and purified from an extract of a germinating black gram seedling. The method was accomplished by gel filtration of a germinating black gram seedling crude extract on sephadex G-75 followed by ion exchange chromatography on DEAE cellulose. The acid phosphatase gave a single band on SDS-polyacrylamide slab gel electrophoresis. The molecular weight of the acid phosphatase determined by SDS-polyacrylamide slab gel electrophoresis was estimated to be 25 kDa. The purified enzyme showed maximum activity at pH 5 and at temperature of 55?C. Mg2+, Zn2+ and EDTA had an inhibitory effect on the activity of the acid phosphatase. Black gram seedling acid phosphatase was activated by K+, Cu2+ and Ba2+. The Km value of the enzyme was found to be 0.49 mM for pNPP as substrate.


1982 ◽  
Vol 60 (11) ◽  
pp. 1007-1013 ◽  
Author(s):  
G. Forstner ◽  
A. Salvatore ◽  
L. Lee ◽  
J. Forstner

Intestinal maltase with a neutral pH optimum exists in both a brush border membrane-bound form and a soluble form in suckling rat intestine. Previous experiments in our laboratory have shown that the soluble enzyme contains a component which binds much more tightly to concanavalin A (ConA) than solubilized forms of the membrane enzyme. We studied the origin of this component by subjecting neutral, soluble maltase activity to chromatography on Sepharose 4B at age 13, 18 (preweaning), and 25 (postweaning) days. At 13 days, two maltase peaks were obtained with approximate molecular weights of 400 000 (peak I) and 150 000 (peak II). Peak II was less prominent at 18 days and was absent at 25 days. At 13 days, the majority of peak I consisted of material which was bound between 0.025 and 0.05 M α-methyl mannoside on gradient elution chromatography of ConA-Sepharose. Peak II contained material which eluted between 0.075 and 0.3 M α-methyl mannoside. At 25 days, all of the soluble maltase eluted between 0.025 and 0.04 M α-methyl mannoside. Peak I and peak II maltases had similar pH optima and Km's for maltase. Peak II maltase had a fourfold greater activity toward glycogen than peak I maltase with approximately the same activity for palatinose, turanose, and trehalose. Both maltases were precipitated by an antibody raised against adult membrane-bound maltase. Soluble maltase with neutral pH activity in the suckling rat intestine, therefore, consists of two immunologically related isozymes which differ in their molecular weight, their binding by ConA, and their specificity for glycogen. The small isozyme disappears at or about the time of weaning.


1980 ◽  
Vol 33 (3) ◽  
pp. 279 ◽  
Author(s):  
RN Murdoch ◽  
Louise E Buxton ◽  
DJ Kay

An improved procedure for the purification of alkaline phosphatase from about 10 g of day 7 pregnant mouse uterine tissue is described. Following homogenization, the procedure involved solubilization and extraction with 0�8% (v/v) Triton X-lOO and 20% (v/v) n-butanol, ammonium sulfate precipitation, concanavalin A-Sepharose 4B affinity chromatography, DEAE-cellulose anion-exchange chromatography and Sephacryl S200 gel filtration. On subjecting 2162-fold purified enzyme preparations to polyacrylamide-gel electrophoresis, a single band of protein coincident with the zone of enzyme activity and having an apparent molecular weight of 205 OOO� lOOOO was identified. Affinity chromatography yielded the largest increase in purity of any step in the procedure and established the glycoprotein nature of the uterine enzyme.


1993 ◽  
Vol 71 (1-2) ◽  
pp. 22-26 ◽  
Author(s):  
Pratima Dutta ◽  
Gopal C. Majumder

A neutral β-D-galactosidase has been partially purified from rat epididymis and characterized. The enzyme having molecular mass of approximately 50 kilodaltons has been purified 400-fold by using calcium phosphate gel adsorption, DEAE-cellulose chromatography, Sephadex G-100 gel filtration, and concanavalin A - agarose affinity chromatography. Although the neutral enzyme binds to the concanavalin A affinity column, the activity could be eluted with α-methyl mannoside only if the buffer contained salt (NaCl) at a concentration as high as 0.3 M. The enzyme was of cytosolic origin, since 90% of the total enzymic activity of the tissue homogenate was recovered in the soluble fraction of these cells. The neutral β-galactosidase was not dependent on metal ions for its activity and it had a pH optimum of 7.0. Zn2+, p-chloromercuribenzoate, Hg2+, and Pb2+ served as potent inhibitors of the enzyme. There was a marked increase (approximately fourfold) in the specific activity of the neutral β-galactosidase during sexual maturity of epididymis in vivo.Key words: neutral β-galactosidase, rat epididymal, cytosolic, developmental, sexual maturity.


1979 ◽  
Vol 183 (2) ◽  
pp. 303-307 ◽  
Author(s):  
K Tryggvason ◽  
K Majamaa ◽  
J Risteli ◽  
K I Kivirikko

Prolyl 3-hydroxylase was purified up to about 5000-fold from an (NH4)2SO4 fraction of chick-embryo extract by a procedure consisting of affinity chromatography on denatured collagen linked to agarose, elution with ethylene glycol and gel filtration. The molecular weight of the purified enzyme is about 160000 by gel filtration The enzyme is probably a glycoprotein, since (a) its activity is inhibited by concanavalin A, and (b) the enzyme is bound to columns of this lectin coupled to agarose and can be eluted with a buffer containing methyl alpha-D-mannoside. The Km values for Fe2+, 2-oxoglutarate, O2 and ascorbate in the prolyl 3-hydroxylase reaction were found to be very similar to those previously reported for these co-substrates in the prolyl 4-hydroxylase and lysyl hydroxylase reactions.


1978 ◽  
Vol 173 (1) ◽  
pp. 191-196 ◽  
Author(s):  
M Carroll

Those proteins of human liver that cross-reacted with antibodies raised to apparently homogenous hexosamindases A and B were detected by immunodiffusion. Cross-reacting proteins with high molecular weights (greater than 2000000) and intermediate molecular weights (70000–200000) were present both in the unadsorbed fraction and in the 0.05–0.2M-NaCl eluate obtained by DEAE-cellulose chromatography at pH7.0. The unadsorbed fraction also contained a cross-reacting protein of low molecular weight (10000–70000). The possible structural and functional relationships between hexosaminidase and the cross-reacting proteins are discussed. An apparently cross-reacting protein present in the 0.05M-NaCl eluate from the DEAE-cellulose column was serologically unrelated to hexosaminidase, but it gave a reaction of immunological identify with one of the apparently cross-reacting proteins having the charge and size characteristics of hexosaminidase A. It is suggested that immunochemical methods may provide criteria for the homogeneity of enzyme preparations superior to those of conventional methods.


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