Isolation of beta-N-acetylhexosaminidase from rabbit semen and its role in fertilization

Beta-N-Acetylhexosaminidase was purified from the rabbit seminal plasma by a three-step procedure involving hydroxyapatite, Sephadex G-200 and concanavalin A--Sepharose chromatography. The specific activity of the purified preparation was 56mu mol/min per mg of protein, which represented a 226-fold purification and a 54% yield of the enzyme activity. The purified enzyme was electrophoretically homogeneous. The homogeneous enzyme showed optimal activity at pH4.0. The apparent Km value and Vmax. were 1.4 mM and 56mu mol/min per mg of protein respectively. Metal ions such as Ag + and Hg2+ and p-chloromercuribenzoate strongly inhibited the enzyme activity. The treatment of rabbit ova with a mixture of Beta-N-acetylhexosaminidase and arylsulphatase A results in the swelling of the zona pellucida.

Purification of glycoside hydrolases from Bacteroides fragilis

Six glycoside hydrolases in the culture medium of Bacteroides fragilis--alpha-glucosidase, beta-glucosidase, alpha-galactosidase, beta-galactosidase, beta-N-acetylglucosaminidase, and alpha-L-fucosidase-were systematically purified by ammonium sulfate precipitation, gel filtration chromatography, and density gradient isoelectric focusing. The isoelectric focusing resolved the glycosidases into distinct, well-separated fractions and revealed three differently charged forms of beta-N-acetylglucosaminidase and of alpha-L-fucosidase. Furthermore, alpha-glucosidase and beta-N-acetylglucosaminidase were shown to possess dual affinities for the respective galactoside substrates, and beta-galactosidase also hydrolyzed beta-D-fucoside. alpha-Glucosidase was purified to homogeneity, as indicated by a thin-layer isoelectric focusing zymogram technique. The glycosidases, with exception of beta-glucosidase and the acid alpha-L-fucosidase, were each separated from other glycosidic activities to 99%. The molecular weights varied between 58,000 and 125,000. The pH optima ranged from 4.8 to 6.9.

Characterization of a novel endo-N-acetyl-beta-D-glucosaminidase from the culture filtrate of a basidiomycete (Sporotricum dimorphosporum), active on biantennary mono- and asialoglycoasparagines of the N-acetyllactosaminic type

A novel endo-N-acetyl-beta-D-glucosaminidase has been characterized in a culture filtrate from a Basidiomycete. This enzyme hydrolyses biantennary monosialo and asialo-glycoasparagines of the N-acetyllactosaminic type. Endo-N-acetyl-beta-D-glucosaminidase from the Basidiomycete released from different glycoasparagines, beta-GlcNAc-(1 leads to 4)-N[14C] acetyl-Asn, alpha Fuc-(1 leads to 6)-beta-GlcNAc-(1 leads to 4)-N-[14C]acetyl-Asn and oligosaccharides which have been separated by paper and thin-layer chromatography. Determination of the radioactivity of the labeled fragments leads to the conclusion that the biantennary glycoasparagines of the N-acetyllactosaminic type are hydrolyzed after 1 h incubation at 37 degrees, to the extent of 15 per cent for the monosialo; 90 per cent for the asialo; 21 per cent for the asialo-monofucosylated, and 15 per cent for the asialo-difucosylated glycans. Tri- and tetraantennary asialo-glycans of the N-acetyllactosaminic type are not hydrolyzed by this enzyme.

Purification and properties of endo-beta-N-acetylglucosaminidase L from Streptomyces plicatus

An enzyme, previously described as endo-beta-N-acetylglucosaminidase L (Tarentino, A.L., and Maley, F. (1974) J. Biol. Chem. 249, 811-817) because of its apparent specificity for Man(GlcNAc)2Asn, has been purified to homogeneity. The enzyme has now been found to hydrolyze (GlcNAc)3 to (GlcNAc)2 plus GlcNAc, and (GlcNAc)4 to 2(GlcNAc)2, at twice the rate observed for Man(GlcNAc)2Asn. Removal of the asparagine from the latter compound reduces the rate of hydrolysis by about 30-fold. Reduction of (GlcNAc)3 to GlcNAc beta 1 leads to 4GlcNAc beta 1 leads to 4GlcNAc-ol eliminates this compound as a substrate for endo-beta-N-acetylglucosaminidase L. However, the reduction of (GlcNAc)4 does not affect its rate of hydrolysis. Endo-beta-N-acetylglucosaminidase L consists of a single polypeptide chain with a molecular weight of 49,500 +/- 400, which on isoelectric focusing separates into two closely migrating bands; a major with a pI of 4.25 and a minor one with a pI 4.20. Both bands possess similar enzyme activities and amino acid compositions, but differ slightly in their tryptic peptide maps.

Alteration of hexosaminidase isozymes in human renal carcinoma

The activity and isozyme patterns of hexosaminidase in human renal carcinoma were studied in comparison with those of normal kidney. Hexosaminidase in extracts from normal kidney and renal carcinoma tissue could be separated into two major forms [hexosaminidase A (Hex A) and hexosaminidase B (Hex B)] by Cellogel electrophoresis or by diethylaminoethyl cellulose column chromatography. All of 10 renal carcinoma tissues showed a low activity ratio of Hex A to Hex B, as compared with the ratio in normal kidney; the ratio in renal carcinoma tissue was between 0.61 and 2.21 (mean, 1.30), while that in normal kidney was between 2.50 and 4.52 (mean, 3.46). Hexosaminidase activity and the ratio of Hex A to Hex B in renal carcinoma tissue were independent of the cell type and the differentiation grade of carcinoma tissue. Hex A and Hex B of renal carcinoma tissue differed from each other in physicochemical properties such as pH dependence of enzyme activity, thermostability, and Km's for two synthetic substrates, but each isozyme maintained its same physicochemical properties whether from normal or from carcinoma tissue. The isozyme patterns of cultured renal carcinoma cells and placenta were similar to those of the carcinoma tissue. The results presented here indicate that hexosaminidase isozymes in renal carcinoma tissue express at least oncoplacental patterns.

"Affinity" chromatography of steroid-transforming enzymes with a non-steroidal ligand

The chromatographic behaviour of an avian oestradiol-17 beta dehydrogenase, the 3(17) beta-hydroxy steroid dehydrogenase from Pseudomonas testosteroni and cortisone reductase from Streptomyces dehydrogenans was studied on columns of p-(phenoxypropoxy)aniline attached to CNBr-activated Sepharose. The ligand was effective in adsorbing the oestradiol dehydrogenase from a partially purified extract of chicken liver, and the cortisone reductase was perferentially retained when mixtures of the three dehydrogenases were applied to columns in 10mM-buffer. Under these conditions the 3(17)beta-hydroxy steroid dehydrogenase was eluted in the front, but was adsorbed in the presence of 3 M-KCl. beta-N-Acetylglucosaminidase present in the liver preparation was not retained by the ligand, whereas lactate dehydrogenase from rabbit muscle was adsorbed in a manner similar to the retention pattern found on affinity chromatography with 2',5'-ADP--Sepharose. The mean overall purification of the oestradiol dehydrogenase was 13-fold, with a mean recovery of 53%. p-(Phenoxypropoxy)aniline offers promise for the purification of steroid-transforming enzymes where elution with substrate or cofactor is not wanted. It is also suggested that the ligand may be of service in the purification of receptors of hormonal steroids.

Purification and characterization of an extracellular beta-n-acetylhexosaminidase from Paecilomyces persicinus

Both beta-N-acetylglucosaminidase nad beta-N-acetylgalactosaminidase activities were detected in the culture fluids of Paecilomyces persicinus P-10 after growth in a soybean meal-corn meal medium. The active material was purified by means of protamine sulfate fractionation and ultrafiltration, followed by ion exchange and gel chromatography. The ratio of the two activities remained constant throughout the purification, and the final product was shown to migrate as a single band by using gel isoelectric focusing, disc electrophoresis, and detergent gel electrophoresis. Temperature, pH, inhibition, and kinetic studies were performed to characterize both activities. The molecular weight of the enzyme was estimated to be about 100,000 by high-resolution gel chromatography. Based on the data obtained, it is suggested that both beta-N-acetylglucosaminidase and beta-N-acetylgalactosaminidase activities reside in the same protein.

Histochemical localization of glycosidases in dog epididymis

The histochemical localization of five glycosidases was studied in the epididymis of mature dogs. beta-Galactosidase showed a distinct to strong reaction in the epithelium of the ductuli efferentes and throughout the whole length of the ductus epididymidis. beta-N-Acetylglucosaminidase reactivity was weak in the initial segment, but increased significantly in the middle and terminal segment. The maximum beta-glucuronidase activity was found in the ductuli efferentes and in the initial segment. The alpha-mannosidase reaction was weak in all segments except the middle segment where a distinct activity was seen. With the method employed, no alpha-fucosidase activity could be detected. The physiological role of the glycosidases in the epididymis is discussed briefly.

N-acetyl-beta-d-glucosaminidase in marmoset kidney, serum and urine

N-Acetyl-beta-D-glucosaminidase activities were determined in homogenates of marmoset kidney, in serum and in urine by using the 4-methylumbelliferyl substrate. The enzyme activity was separated into several components by DEAE-cellulose ion-exchange chromatography, starch-gel electrophoresis and isoelectric focusing. The kidney contained two major forms of the enzyme, A and B, which had similar pH optima and Km values. The A-form bound to DEAE-cellulose at pH 6.8, migrated towards the anode on starch-gel electrophoresis and had a pI of 5.0. The B-form did not bind to DEAE-cellulose at pH 6.8, remained near the origin on starch-gel electrophoresis and had a pI of 7.64. The isoenzymes also differed in heat stability, the B-form being the more stable. Serum contained B-form activity and, in addition, two intermediate forms (I1 and I2) were loosely bound to DEAE-cellulose. The serum A-form activity was less firmly bound to DEAE-cellulose than was the tissue A-form and was designated As. Serum from a pregnant marmoset contained a form which may be analogous to the human P-isoenzyme. Urine contained only a small amount of B-form activity, the majority being present in the A-form. The kidney A- and B-forms both had mol.wts. of 96000--100000 and the activity was predominantly lysosomal. Partial purification of the kidney A isoenzyme was undertaken. Immunoprecipitation studies indicated a relationship between marmoset kidney A-form and human liver A-form activity.

Human placenta alpha-N-acetylglucosaminidase: purification, characterization and demonstration of multiple recognition forms

alpha-N-Acetylglucosaminidase (EC 3.2.1.50) was purified from human placenta by a four-step procedure including ammonium sulfate precipitation, affinity chromatography with immobilized antibodies against urinary alpha-N-acetylglucosaminidase, gel chromatography and discontinuous gel electrophoresis with a 30% recovery and 26 300-fold purification. Immunological methods revealed the contamination with about 10% non-alpha-N-acetylglucosaminidase protein. Isoelectric focusing led to a distribution of activity between 4.3 and 6.5 with maxima at pH 5.1 and pH 5.7. After treatment with neuraminidase, alpha-N-acetylglucosaminidase activity assembled at pH 5.7. The multiple isoelectric forms were endocytosed with different rates by cultured human skin fibroblasts. Placenta alpha-N-acetylglucosaminidase has an apparent molecular weight of 304 000 and contains 23.4% carbohydrate consisting of glucose, galactose, mannose, hexosamines and neuraminic acid. Gel electrophoresis in the presence of 0.1% sodium dodecylsulfate separated placenta alpha-N-acetylglucosaminidase into subunits with molecular weights of 86 500 and 81 000. The activity towards various substrates, the kinetics of hydrolysis, the pH optimum and the stability of the catalytic activity were assayed.

[Purification and properties of beta-N-acetylglucosaminidase from Mytilus edulis L. gonads (author's transl)]

beta-N-Acetylglucosaminidase (beta-2-acetamido-2-deoxy-D-glucoside acetamidodeoxyglucohydrolase EC 3.2.1.30) from Mytilus edulis gonads and a homogenous protein was obtained from it by ion-exchange chromatography, gel filtration and disc electrophoresis. The apparent molecular weight, determined by gel filtration was 140,000 +/- 5,000. Two subunits were identified. The molecular weights of both subunits calculated by disc-electrophoresis were 70,000 and 75,000 + 2,000. Maximal activity for pH was 4.2. At 50 degrees C the enzyme was still active; at 60 degrees C inactive. The values of the apparent Km's proved to be 0.57 mM and 0.076 mM for p-nitrophenyl-beta-D-N-acetylglucosaminide and p-nitrophenyl-beta-D-N-acetylgalactosaminide as substrates. In the incubation of the enzyme with hyaluronic acid, chitin, deacetilated glycol-chitin and p-nitrophenyl-beta-D-glucuronide, N-acetyl-beta-D-glucosamine and glucuronic acid were not liberated. N-acetylgluconolactone and N-acetylgalactonolactone are competitive inhibitors for the enzyme.

The multiple forms and kinetic differences of rat colonic beta-N-acetylhexosaminidases

Rat colonic beta-N-acetylhexosaminidase (2-acetamido-2-deoxy-beta-D-glucoside acetamidodeoxyglucohydrolase, EC 3.2.1.30) has been separated into three forms by DEAE-cellulose chromatography with an increasing salt gradient. It was not possible to separate the glucosaminidase activity from the galactosaminidase activity by a variety of chromatographic procedues, but the ratio of the two specific activities varied during purification. The pH optima were however identical, for both activities and all three forms. Kinetic measurements including inhibition by substrate analogues showed differences between the two activities as well as among the three forms. A common active site model was inconsistent with the results. Data from mixed substrate experiments were consistent with a model wherein the two activities reside in seperate active sites, each able to be inhibited by the substrate for the other site. The effect of acetate and SH reagents confirmed the two-site model. Treatment with neuraminidase, thimerosal, p-hydroxymercuribenzoate, HgCl2 and AgNO3 or heating at 50 degrees C did not produce any effect on the A form that could be identified as a conversion to the B form. Measurement of the effects on both activities supported the two-site model. It is concluded that the relationship between the A and B forms in the rat colonic mucosa hexosaminidases must be different from that reported for such enzymes from other sources.

Further studies on endo-beta-N-acetylglucosaminidase D1

The purification procedure for endo-beta-N-acetylglucosaminidase D was improved to yield an enzyme preparation which was homogeneous upon gel electrophoresis. The molecular weight of the enzyme as estimated by Sephadex G-200 column chromatography was 280,000, while SDS-gel electrophoresis after reduction with 2-mercaptoethanol gave a value of 150,000. The purified enzyme did not show any chitinase, hyaluronidase or lysozyme activity. In the presence of exoglycosidases removing peripheral sugars, the endoglycosidase acted on serum glycoproteins such as transferrin and fetuin. The enzyme also hydrolyzed an oligosaccharide, (Man)5(GlcNAc)2, indicating that the peptide portion of substrates does not have much effect on susceptibility to the enzyme.

Isoenzymes of N-acetyl-beta-glucosaminidase from human liver and serum: separation by electrofocusing in thin layers of polyacrylamide gel

Isoenzymes of N-acetyl-beta-glucosaminidase can be separated by electrofocusing in thin layers of polyacrylamide gel. Patterns of isoenzymes from human liver tissue and serum show changes in liver diseases. Preliminary results indicate, that N-acetyl-beta-glucosaminidase isoenzyme A is increased in liver tissue from patients with chronic liver diseases in relation to the activity of mesenchyme reaction. The described method will be discussed in comparison with known separation techniques.

Separation of beta-N-acetylglucosaminidase isoenzymes from liver and plasma of six mammalian species by DEAE-cellulose chromatography

1. The beta-N-acetylglucosaminidase (EC 3.2.1.30) activities of human, pig, calf, lamb, rat and rabbit liver and plasma have been investigated. 2. All preparations had maximum activity between pH 4.0 and 4.5 and Km values with the substrate 4-methylumbelliferyl-2-acetamido-2-deoxy-beta-D-glucopyranoside ranged from 0.54 to 2.54 mM. 3. The isoenzyme profiles of liver and plasma beta-N-acetylglucosaminidase activity were compared using DEAE-cellulose chromatography. In all species the major anionic component of liver (beta-N-acetylglucsaminidase A) was eluted at a higher salt concentration than the most anionic plasma isoenzyme. 4. The plasma beta-N-acetylglucosaminidase A isoenzyme of all species contained sialic acid residues whereas only the rabbit, pig and calf liver isoenzymes were sialylated.