Alpha-Aminoadipate aminotransferase and kynurenine aminotransferase. Purification, characterization, and further evidence for identity

Alpha-Aminoadipate aminotransferase and kynurenine aminotransferase activities were co-purified from the rat kidney supernatant fraction. The resulting preparation was determined to be nearly homogenous by analytical disc gel electrophoresis at pH 8.9 and 7.5 isoelectric focusing on polyacrylamide gels, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. A molecular weight of approximately 85,000 was determined on Sephadex G-200 chromatography and sucrose density gradient analysis. The enzyme was determined to be comprised of two subunits of approximately the same molecular weight (45,500 +/- 850) by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. An isoelectric pH of 6.56 +/- 0.06 was determined by focusing on polyacrylamide gels. Further evidence is provided to support the idea that the alpha-aminoadipate aminotransferase and kynureine aminotransferase activities are properties of a single protein: (a) co-purification of the two activities from the rat kidney supernatant fraction with the ratio of their specific activities remaining constant, (b) similar chromatographic behavior, (c) a similarity in their dependence on added pyridoxal-P for activity, and (d) a similar pattern of heat inactivation.     

Partial purification of box jellyfish (Chironex fleckeri) nematocyst venom isolated at the beachside

Chironex fleckeri, the northern Australian box jellyfish produces one of, if not, the most potent animal venoms. Study of the venom has been hampered by the limits of the animals' range and the venom's thermolability. Using retained lethality and native polyacrylamide gel electrophoresis (NPAGE), we show that lyophilization of autolysis isolated nematocysts is an effective method of transporting the venom. In addition, Sephadex G-200 chromatography, spin concentration, and NPAGE fail to demonstrate the presence of a 600 kDa protein to which the bulk of the lethal activity has been ascribed. Sodium dodecyl sulfate capillary electrophoresis of crude venom yields several protein bands with a molecular weight range of 30-200 kDa. Freeze-thaw studies show a loss of activity and NPAGE bands after two freeze thaw cycles.     

Physico-chemical properties of a protein-inhibitor of serine proteinases from the potato]

Serine proteases inhibitor with pl-7.3, isolated from potatoe tubers by isoelectric focusing procedure as described previously (V.V. Mosolov et al., Bioorganic Chem., 1, 1449, 1975), was homogeneous under ultracentrifugation, having sedimentation coefficient S20,w 2.8S. Its molecular weight, investigated by sedimentation equilibrium and gel filtration through Sephadex G-100, was found to be 32500 and 31500 respectively. The Stokes radius R and frictional ratio f/fo were found to be 24 A and 1.14. The molecular weight of the inhibitor as determined by sodium dodecylsulfate polyacrylamide electrophoresis was twice as low as determined in ultracentrifuge and by gel filtration procedure. It is suggested that the inhibitor is dimer and consists of two protomers of equal molecular weight.     

Purification of two murine monoclonal antibodies of the IgM class by hydroxylapatite chromatography and gel filtration

A two-step method using hydroxylapatite chromatography and gel filtration is described for the purification of two murine monoclonal antibodies of the IgM class. Ascites fluid from each hybridoma was diluted in sodium phosphate buffer (0.01 M, pH 6.8), loaded onto a hydroxylapatite column and eluted with a stepwise sodium phosphate gradient. The immunoreactive protein peaks were concentrated and subjected to gel filtration using either Sephadex G-200 or Sephacryl S-200HR. The biological activity of the end-products was confirmed by complement lysis assay and by indirect immunofluorescence and flow cytometry. The purity of the end-products as assessed by SDS polyacrylamide gel electrophoresis and densitometry was at least 90%. The methods described produced immunoreactive material with a high level of purity. The procedure for each antibody was reproducible and provides a reliable method for purification of monoclonal antibodies of the IgM class.     

Purification of rat liver nuclear protein kinase NII

Rat liver nuclear protein kinase activity (NII), which is eluted from DEAE-Sephadex columns, has been purified approximately 1500-fold from solubilized nuclear protein. The method of purification involved chromatography of protein eluted from DEAE-Sephadex successively on phosvitin-Sepharose, mixed histone-Sepharose, and histone H2b-Sepharose followed by gel filtration on Sephadex G-200. Resulting preparations are homogeneous by polyacrylamide gel electrophoresis. The enzyme consists of three polypeptides with molecular weights of 42,000 (alpha), 39,000 (alpha'), and 26,000 (beta) which are present in the ratio 1:1:2 indicating that the enzyme has a minimum tetrameric subunit composition of alphaalpha'beta2. The molecular weight and s20,w of the purified enzyme were 123,000 and 7.0, respectively, as determined by sucrose density gradient centrifugation in 0.4 M NaCl. The enzyme has maximal activity with phosvitin as substrate and is not stimulated by 10(-5) to 10(-4) M cAMP or cGMP using H2b as substrate.     

Isolation and characterisation of glutamate dehydrogenase from Mycobacterium smegmatis CDC 46

Glutamate dehydrogenase (L-glutamate:NADP+ oxidoreductase (deaminating), EC 1.4.1.4) has been purified from Mycobacterium smegmatis CDC 46 using (NH4)2SO4 precipitation, negative adsorption on DEAE-cellulose, 2',5'-ADP-Sepharose affinity chromatography and Sephadex G-200. The enzyme was purified 1041.6-fold and the preparation was found to be homogeneous on column chromatography, polyacrylamide gel electrophoresis and SDS-polyacrylamide gel electrophoresis. Alanine and threonine were identified as the N- and C-terminal amino acids of glutamate dehydrogenase from M. smegmastis. The enzyme kinetics and regulation of glutamate dehydrogenase activity by different nutritional factors has been studied. Initial velocity plots showed that the reaction mechanism of glutamate dehydrogenase from M. smegmatis followed an ordered sequential ter-bi mechanism.     

Further purification and characterization of macromomycin

The antitumor polypeptide, macromomycin (MCR) produced by Streptomyces macromomyceticus, was purified by ammonium sulfate precipitation, ultrafiltration and chromatographic techniques using Amberlite IRA-410, DEAE Sephadex A-25 (CI- and OH-type) and Sephadex G-50. Purified MCR was obtained as a white powder by lyophilization. MCR, thus purified, exhibited a single peak on Sephadex G-50 chromatography with no detectable contaminant by ultracentrifugation and polyacrylamide gel electrophoresis. MCR is an acidic polypeptide having an isoelectric point of pH 5.4. It contains no arginine and methionine. The molecular weight was 11,700, 12,500 and 11,400 by amino acid composition, gel filtration and analytical ultracentrifugation, respectively. MCR is labile as a lyophilized powder but is successfully stabilized by the addition of maltose.     

Studies on the glycosidases of semen. Further purification and characterization of two hexosaminidases from bull seminal plasma

Two isozymes of beta-N-acetylglucosaminidase (2-acetamido-2-deoxy-beta-D-glucoside acetamidodeoxy glucohydrolase, EC 3.2.1.30) (A and B) from bull seminal plasma were purified to homogeneity by isoelectric focusing having pI values of 5.31 and 6.78. The two proteins were glycoproteins with very similar amino acid composition but isozyme A contained more sialic acid than isozyme B. The molecular weights of isozyme A and B were estimated at 200 000 and 190 000 by gel filtration. Two identical subunits corresponding to molecular weights of 53 000 and 13 400 were obtained from hexosaminidase A and B when subjected to polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate. Similar results were obtained when dissociation of the isozymes was effected with mercaptoethanol, guanidine hydrochloride and urea in presence of sodium dodecyl sulphate and the subunits separated by acrylamide gel electrophoresis. The two isozymes were more stable in frozen conditions than at the refrigerated temperature. Of the divalent ion tested, glucosaminidase and galactosaminidase activities of isozymes A and B were strongly inhibited by Hg2+ and Ag+ thus suggesting the presence of thiol groups in the two proteins. The two isozymes were active on natural substrates; isozyme B being more active than isozyme A.     

Partial purification and kinetic studies of exocellular proteinase from Trichophyton mentagrophytes var. erinacei

The dermatophyte Trichophyton mentagrophytes var. erinacei isolated from a patient with tinea cruris was cultured in peptone-glucose broth from which an exocellular proteinase was obtained. The enzyme was partly purified by Sephadex G-100 gel filtration. Its molecular weight was determined to be 33,000 on sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The optimal pH was 8.5, the optimal temperature 35 degrees C. The proteolytic activity was specifically increased against casein and inhibited by phenylmethylsulphonyl fluoride. The enzyme was identified as alkaline serine proteinase.     

Purification of C3b inactivator and demonstration of its two polypeptide chain structure

C3b inactivator (C3bINA) was isolated from plasma by sequential ammonium sulfate gradient solubilization, anion exchange chromatography, gel filtration, and repeat ammonium sulfate gradient solubilization. The final product was pure as assessed by alkaline disc gel electrophoresis, isoelectric focusing, and SDS polyacrylamide gel electrophoresis, and elicited a monospecific rabbit antiserum. The normal serum concentration of C3bINA was found to be 53 +/- 9 microgram/ml (mean +/- S.D.). Heterogeneity of purified C3bINA was apparent on alkaline disc gel electrophoresis and isoelectric focusing, but not with SDS polyacrylamide gel electrophoresis and thus is attributed to forms of C3bINA that differ in charge rather than in size. SDS polyacrylamide gel electrophoresis of unreduced, alkylated C3bINA yielded a single stained band with an apparent m.w. of 93,000, whereas the reduced protein demonstrated two bands of 55,000 and 42,000 m.w., thereby establishing a composition of two disulfide-linked polypeptide chains for C3bINA.     

Human pancreatic alpha-amylase. I. Purification and characterization

alpha-Amylase was extracted from human pancreas and purified by using ammonium sulfate fractionation, Sephadex G-100 and DEAE-Sephadex A-50 column chromatography. The enzyme was shown to be homogenous by three different criteria: polyacrylamide disc gel electrophoresis, SDS polyacrylamide gel electrophoresis and analytical ultracentrifugation. The values of SO20,w, D20,w, v, and frictional ration of the enzyme were calculated to be 5.01S, 7.56D, 0.718 ml g-1 and 1.10, respectively. The molecular weight of the alpha-amylase was determined by three different methods: sedimentation velocity-diffusion, conventional sedimentation equilibrium and SDS polyacrylamide gel electrophoresis and was found to be 57,850; 50,100 and 53,200 g mole-1, respectively (average value 53,700). The amino acid composition of the enzyme was determined and compared with those of alpha-amylases from various other sources.     

Purification and properties of dipeptidyl amino-peptidase I from chicken liver (author's transl)

Dipeptidyl aminopeptidase I (E.S. 3.4.14.1) from chicken liver was purified by the following steps: homogenization at pH 5, thermic precipitation, acetone fractionation and Sephadex G-100, DEAE-cellulose and organomercurial-Sepharose column fractionations. The purified enzyme appears to be homogeneous by polyacrylamide gel electrophoresis at both pH 4.5 and 8.3 and has an isoelectric point of 5.7 +/- 0.05. The molecular weight of the enzyme reale 167,000 +/- 17,000 on the Sephadex G-150 column chromatography. The optimum pH for hydrolysis of Gly-Phe-p-nitroanilide (GPNA) and Gly-Phe-B-naphthylamide was 5.8. The value of Km for the hydrolysis of GPNA was estimated at 3.3 mM. The enzyme required halide ions for activity and was activated by thiol reagents (dithiothreitol, cysteine and 2-mercaptoethanol). Accordingly, DAP I was inhibited by thiol-blocking reagents (PCMB, IAA, Hg2+). The enzyme oxidation with oxygen current was fostered by chloride anion (50 nM); nevertheless the activity was recovered when cysteine was present in the incubation mixture; the latter, besides, seems to perform as enzyme protector.     

Cathepsin D from horse spleen. I. Purification and study of certain physicochemical properties

Horse spleen cathepsin D (3.4.23.5.) was purified from crude extract by sodium chloride and ethanol precipitation, column chromatography fractionation on DEAE cellulose and CM Sephadex, re-chromatography on DEAE cellulose and gel filtration. The enzyme has been purified about 3.000 folds with a yield of 30 per cent. The purified enzyme seems to be homogeneous on Sephadex G100, one protein band is apparent on disc electrophoresis. Determined by dansylation the N-terminal amino acid is glycine. A molecular weight of 42,500 +/- 3,000 was obtained with Sephadex G100 gel filtration and light scattering measurements. Amino acid analysis and chemical determinations were performed: cathepsin D is a glycoprotein (2 or 3 osamine residues) including 344 amino acids and 4 disulfide bonds. Spectrophotometric data show that E1cm/1 mg/ml = 1.01 at lambda = 280 nm. ORD measurements indicate about 20 per cent of helicoidal content in the molecule.     

The mediation of tissue eosinophilia in hypersensitivity reactions. II. Separation of a delayed eosinophil chemotactic factor from macrophage chemotactic factors

In anaphylactic cutaneous lesions induced by DNP-ascaris extract in the guinea-pig, the time-course of delayed tissue eosinophilia was found to parallel that of the macrophage reaction, reaching its peak in 24 h. Macrophages could be differentiated from lymphocytes by the numerous lysosomal granules which stained for acid phosphatase. Extracts from such skin lesions contained a delayed eosinophil chemotactic factor and two different macrophage chemotactic factors. Most of the delayed eosinophil chemotactic factor was separated from the two macrophage chemotactic factors by gel filtration on Sephadex G-100 and Sephadex G-200 in that order. The eosinophil chemotactic factor after re-chromatography on Sephadex G-I99 showed no or little chemotactic activity for macrophages.     

Purification and characterization of a neutral, bile salt-independent retinyl ester hydrolase from rat liver microsomes. Relationship To rat carboxylesterase ES-2

A neutral, bile salt-independent retinyl ester hydrolase (NREH) has been purified from a rat liver microsomal fraction. The purification procedure involved detergent extraction, DEAE-Sepharose ion exchange, Phenyl-Sepharose hydrophobic interaction, Sephadex G-100 and Sephacryl S-200 gel filtration chromatographies, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The isolated enzyme has an apparent molecular mass of approximately 66 kDa under denaturing conditions on SDS-PAGE. Analysis of the amino acid sequences of four peptides isolated after proteolytic digestion revealed that the enzyme is highly homologous with other rat liver carboxylesterases. In particular, the sequences of the four peptides of the NREH (60 amino acids total) were identical to those of a rat carboxylesterase expressed in the liver (Alexson, S. E. H., Finlay, T. H., Hellman, U., Svensson, L. T., Diczfalusy, U., and Eggertsen, G. (1994) J. Biol. Chem. 269, 17118-17124). Antibodies against this enzyme also react with the purified NREH. Purified NREH shows a substrate preference for retinyl palmitate over triolein and did not catalyze the hydrolysis of cholesteryl oleate. With retinyl palmitate as substrate, the enzyme had a pH optimum of 7 and showed apparent saturation kinetics, with half-maximal activity achieved at substrate concentrations (Km) of approximately 70 microM.     

Isolation of myotoxic component from rattlesnake (Crotalus viridis viridis) venom. Electron microscopic analysis of muscle damage

The pathogenesis of myonecrosis induced by a purified component of rattlesnake (Crotalus viridis viridis) venom was studied at the light and electron microscopic levels. Crude venom was fractionated by gel filtration (Sephadex G-50) followed by cation exchange chromatography (Sephadex C-25). Electrophoretic homogeneity of the isolated myotoxin (Fraction II from C-25 column) was demonstrated in isoelectric focusing and disc gel polyacrylamide gel electrophoresis. White mice were injected intramuscularly with 1.5 mug/g of the purified protein in 0.1 ml of physiologic saline. Light microscopic examination of injected muscle revealed a series of degenerative events including partial vacuolation of muscle cells at 6, 12, and 24 hours and complete vacuolation and loss of striations at 48 and 72 hours. Hemorrhage was not observed. At the electron microscopic level the perinuclear space and sarcoplasmic reticulum were dilated in all samples. By 48 and 72 hours the myofibrils lacked striations and the sarcomeres were disorganized. Plasma membranes and T tubules remained intact in all samples. These results correlated well with the myonecrosis induced by crude Crotalus viridis viridis venom except for several important aspects. The pure component altered skeletal muscle cells specifically, with the sarcoplasmic reticulum being the primary site of action.     

Purification and some properties of maleylpyruvate hydrolase and fumarylpyruvate hydrolase from Pseudomonas alcaligenes

Hydrolysis of the gentisate ring-cleavage product, maleylpyruvate (cis-2,4-diketohept-5-enedioic acid), was shown to be catalyzed by an enzyme, maleylpyruvate hydrolase 11, in Pseudomonas alcaligenes (P25X1) after growth with 3-hydroxybenzoate. This activity was separated from fumarylpyruvate hydrolase activity during the course of its purification which accomplished an approximately 50-fold increase in specific activity. An apparent molecular weight of 77,000 was assigned on the basis of Sephadex G-200 chromatography. Despite the presence of up to three similarly migrating bands of protein on polyacrylamide-gel electrophoresis of the purified enzyme, at least two of these bands possessed maleylpyruvate hydrolase activity. Electrophoresis on sodium dodecyl sulfate-polyacrylamide before and after reduction with mercaptoethanol gave a principal band of molecular weight of 33,000 (and a minor band of molecular weight 50,000). A number of substituted maleylpyruvates also served as substrates for maleylpyruvate hydrolase 11, but maleylacetoacetate and fumarylpyruvate were not attacked. Fumarylpyruvate hydrolase was purified approximately 40-fold to give a single band on polyacrylamide gels and with an apparent molecular weight of 73,000 by Sephadex G-200 chromatography. Upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis before or after reduction with mercaptoethanol, a subunit molecular weight of 25,000 was obtained. Neither maleylpyruvate nor fumarylacetoacetate served as substrates for fumarylpyruvate hydrolase. The activities of both maleyl- and fumarylpyruvate hydrolases were stimulated by Mn(2+) ions. Reasons are discussed for the presence of both enzyme activities, one of which appears to be redundant.     

Chemical and physical properties of the human urinary glycoprotein with gastric antisecretory activity

The chemical and physical properties of the high-molecular-weight glycoprotein (SO20, w = 8S; Ve=Vo on Sephadex G-200) with gastric antisecretory activity extracted from the urine of pregnant women were studied. Gel filtration in the presence of sodium dodecyl sulphate and sodium dodecyl sulphate/polyacrylamide-disc-gel electrophoresis indicated subunit mol.wts. of 16 000 +/- 1500 and 13 000 +/- 1000 respectively. Reaggregation of the subunits and partial recovery of the biological activity were observed on removal of the detergent. The partial C-terminal sequence was found to be Phe-Tyr-Leu-Val-OH, whereas glycine appears to be the N-terminal amino acid. The carbohydrate composition was examined; all galactosamine was found to be O-glycosidically linked to the polypeptide chain.     

Further purification and characterization of serum proteins used to detect cystic fibrosis genotypes by isoelectric focusing

Sera from cystic fibrosis (CF) homozygotes and obligate heterozygotes contain a CF factor (gamma CF factor) not found by isoelectric focusing in thin-layer polyacrylamide gels in most normal control sera. In addition, sera from most obligate heterozygotes lack another protein (bland B, C, or D) that is commonly found in sera from most normal and cystic fibrosis individuals. A standardized, biophysical assay is described that employs isoelectric focusing for the detection of both CF homozygotes and heterozygotes based on the analysis of whole serum for the presence of the gamma CF factor and bands B, C, and D. Results of analyzing sera from selected CF patients by isoelectric focusing indicated that there is a general correlation between the amount of the gamma CF factor and the clinical severity of the disease. Partial purification and characterization of the gamma CF factor and protein bands B, C, and D was accomplished by using DEAE-cellulose chromatography, Sephadex G-200 gel filtration, sequential molecular filtration through a series of Amicon Diaflo ultrafiltration membranes, affinity chromatography, and cellulose acetate electrophoresis. The gamma CF factor is a cationic protein with a pI of 8.46+/-0.05, has gamma electrophoretic mobility, a molecular weight between 3,500 and 10,000, and apparently exists in CF serum in 2 forms (free in solution and complexed to IgG). Bands B, C, and D are cationic proteins with pI values of 7.85 to 8.10, have gamma electrophoretic mobility and a molecular weight of approximately 100,000-150,000.     

Bacteriophage MX-1: properties of the phage and its structural proteins

Bacteriophage MX-1 is a virulent DNA phage for Myxococcus. The host range includes strains of Myxococcus xanthus, M. fulvus and M. virescens. The phage has a sedimentation coefficient (S degrees 20,w) of 1145S and a density of 1-531 g/ml. By using SDS-polyacrylamide gel electrophoresis, 23 phage proteins with apparent mol. wt. between 10000 and 150000 were resolved. Gel filtration in the presence of non-ionic detergent partially resolved the proteins. The fraction excluded from Sephadex G-100, fraction 1, contains two glycoproteins. Fraction 1 was resolved into three fractions (1-1, 1-2 and 1-3) by chromatography on Sephadex G-200. The glycoproteins were present in fraction 1-2; all the proteins from this fraction were derived from the phage tail. Comparison of the amino-acid, hexosamine and neutral-sugar compositions of the two glycoproteins showed that they are distinct molecular species; the smaller molecule is not a subunit of the larger. The significance of these findings is discussed and compared with the proteins of the tails of T-even phage of Escherichia coli.