scholarly journals Immunologically reactive tryptic fragments of human prostatic acid phosphatase

1984 ◽  
Vol 223 (3) ◽  
pp. 871-877 ◽  
Author(s):  
C L Lee ◽  
S S L Li ◽  
T M Chu

Three peptide fragments (designated II, III and IV) of human prostatic acid phosphatase (PAP) were isolated to homogeneity from a limited tryptic hydrolysate of PAP by gel filtration on Sephadex G-100, followed by chromatography on DEAE-cellulose and Sephadex G-75. The homogeneity was confirmed by disc poly-acrylamide-gel electrophoresis. The Mr values were 32 500, 25 000 and 11 000 as estimated by gel filtration and sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. Immunoprecipitation study revealed that only fragment II formed an immune precipitate with anti-PAP antibodies. Fragment II exhibited 45% of maximum inhibitory activity on the reaction between PAP and goat anti-PAP IgG (immunoglobulin G) antibodies (or rabbit anti-PAP antibodies), whereas fragments III and IV demonstrated 24% (or 23%) and 29% (or 27%) inhibition respectively. A mixture of these three tryptic fragments of PAP result in 96% (for goat anti-PAP antibodies) and 94% (for rabbit anti-PAP antibodies) inhibitory activities, which were equivalent to the sum of maximum inhibitory activity of the three fragments individually. The results demonstrated that these three tryptic peptide fragments carried all the antigenic active sites of the native PAP, and suggested that the entire molecule of human PAP comprised a minimum of four distinguishable, nonoverlapping antigenic determinants. These three fragments also were shown to retain all the disulphide bonds of the native PAP, and thus were useful reagents for the elucidation of PAP molecular structure.

1974 ◽  
Vol 77 (3) ◽  
pp. 485-497 ◽  
Author(s):  
P. A. Torjesen ◽  
T. Sand ◽  
N. Norman ◽  
O. Trygstad ◽  
I. Foss

ABSTRACT Highly purified human LH, FSH and TSH were isolated from batches of 300 frozen pituitary glands (200 g) by pH, acetone and ethanol fractionation, Sephadex gel filtration, ion-exchange chromatography on DEAE-cellulose and CM-Sephadex, and preparative polyacrylamide-gel electrophoresis. Sodium dodecyl-sulphate (SDS) polyacrylamide gel electrophoresis was used in order to check the purity, the identity and the molecular weight of the purified LH, FSH and TSH. This procedure showed that the hormone preparations consisted of two subunits with molecular weights of: LH: 21 300 and 17 900, FSH: 22 100 and 18 300 and TSH: 20 800 and 16 400. The purity of the hormone preparations was also evaluated by analytical disc electrophoresis at pH 8.9. The purified hormone preparations had radioimmunological activity as follows: LH: 20 000 IU/mg, FSH: 16 500 IU/mg and TSH: 5 IU/mg. All preparations had high biological potency.


1981 ◽  
Vol 197 (2) ◽  
pp. 427-436 ◽  
Author(s):  
G A Nimmo ◽  
J R Coggins

Neurospora crassa contains three isoenzymes of 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase, which are inhibited by tyrosine, tryptophan and phenylalanine respectively, and it was estimated that the relative proportions of the total activity were 54%, 14% and 32% respectively. The tryptophan-sensitive isoenzyme was purified to homogeneity as judged by polyacrylamide-gel electrophoresis and ultracentrifugation. The tyrosine-sensitive and phenylalanine-sensitive isoenzymes were only partially purified. The three isoenzymes were completely separated from each other, however, and can be distinguished by (NH4)2SO4 fractionation, chromatography on DEAE-cellulose and Ultrogel AcA-34 and polyacrylamide-gel electrophoresis. Polyacrylamide-gel electrophoresis in the presence of sodium dodecyl sulphate indicated that the tryptophan-sensitive isoenzyme contained one type of subunit of molecular weight 52000. The molecular weight of the native enzyme was found to be 200000 by sedimentation-equilibrium centrifugation, indicating that the enzyme is a tetramer, and the results of cross-linking and gel-filtration studies were in agreement with this conclusion.


1978 ◽  
Vol 175 (2) ◽  
pp. 449-454 ◽  
Author(s):  
J Berüter ◽  
J P Colombo ◽  
C Bachmann

Arginase was isolated from human liver and erythrocytes. The purification procedure used acetone precipitation, heat-treatment, (NH4)2SO4 precipitation, DEAE-cellulose chromatography and gel filtration on Sephadex G-200 in the presence of 2-mercaptoethanol. Both enzymes migrated to the anode at pH8.3 on polyacrylamide-gel electrophoresis. After incubation at pH8.0 and 37 degrees C the purified anionic liver arginase migrated to the cathode on polyacrylamide-gel electrophoresis. It is assumed that the multiple forms of the enzyme reported in the literature are partly artifacts of the purification procedure. The liver arginase showed a mol.wt. of 107000 determined by gel filtration and a sedimentation coefficient of 5.9S. Treatment of the liver enzyme with 0.25% sodium dodecyl sulphate at pH10 demonstrated an oligomeric structure of the enzyme with a mol.wt. of the subunit of 35000. The kinetic properties determined for the purified liver arginase showed an optimum pH of 9.3 and an optimal MnCl2 concentration of 2mM. The Km for L-arginine was 10.5 mM and for L-canavanine 50mM, and L-lysine exhibited a competitive type of inhibition with a Ki of 4.4mM. L-Homoarginine was not a substrate for liver arginase.


1985 ◽  
Vol 226 (1) ◽  
pp. 147-153 ◽  
Author(s):  
D B Harper ◽  
J T Kennedy

An enzyme catalysing the O-methylation of isobutyraldoxime by S-adenosyl-L-methionine was isolated from Pseudomonas sp. N.C.I.B. 11652. The enzyme was purified 220-fold by DEAE-cellulose chromatography, (NH4)2SO4 fractionation, gel filtration on Sephadex G-100 and chromatography on calcium phosphate gel. Homogeneity of the enzyme preparation was confirmed by isoelectric focusing on polyacrylamide gel and sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. The enzyme showed a narrow pH optimum at 10.25, required thiol-protecting agents for activity and was rapidly denatured at temperatures above 35 degrees C. The Km values for isobutyraldoxime and S-adenosyl-L-methionine were respectively 0.24 mM and 0.15 mM. Studies on substrate specificity indicated that attack was mainly restricted to oximes of C4-C6 aldehydes, with preference being shown for those with branching in the 2- or 3-position. Ketoximes were not substrates for the enzyme. Gel filtration on Sephadex G-100 gave an Mr of 84 000 for the intact enzyme, and sodium dodecyl sulphate/polyacrylamide-gel electrophoresis indicated an Mr of 37 500, suggesting the presence of two subunits in the intact enzyme. S-Adenosylhomocysteine was a powerful competitive inhibitor of S-adenosylmethionine, with a Ki of 0.027 mM. The enzyme was also susceptible to inhibition by thiol-blocking reagents and heavy-metal ions. Mg2+ was not required for maximum activity.


1983 ◽  
Vol 215 (1) ◽  
pp. 45-55 ◽  
Author(s):  
G H Elder ◽  
J A Tovey ◽  
D M Sheppard

Uroporphyrinogen decarboxylase (EC 4.1.1.37) has been purified 4419-fold to a specific activity of 58.3 nmol of coproporphyrinogen III formed/min per mg of protein (with pentacarboxyporphyrinogen III as substrate) from human erythrocytes by adsorption to DEAE-cellulose, (NH4)2SO4 fractionation, gel filtration, phenyl-Sepharose chromatography and polyacrylamide-gel electrophoresis. Progressive loss of activity towards uroporphyrinogens I and III occurred during purification. Experiments employing immunoprecipitation, immunoelectrophoresis and titration with solid-phase antibody indicated that all the uroporphyrinogen decarboxylase activity of human erythrocytes resides in one protein, and that the substrate specificity of this protein had changed during purification. The purified enzyme had a minimum mol.wt. of 39 500 on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. Gel filtration gave a mol.wt. of 58 000 for the native enzyme. Isoelectric focusing showed a single band with a pI of 4.60. Reaction with N-ethylmaleimide abolished both catalytic activity and immunoreactivity. Incubation with substrates or porphyrins prevented inactivation by N-ethylmaleimide. An antiserum raised against purified erythrocyte enzyme precipitated more than 90% of the uroporphyrinogen decarboxylase activity from human liver. Quantitative immunoprecipitation and crossed immunoelectrophoresis showed that the erythrocyte and liver enzymes are very similar but not identical. The differences observed may reflect secondary modification of enzyme structure by proteolysis or oxidation of thiol groups, rather than a difference in primary structure.


1977 ◽  
Vol 167 (3) ◽  
pp. 685-692 ◽  
Author(s):  
David B. Harper

1. A strain of the fungus Fusarium solani able to use benzonitrile as sole source of carbon and nitrogen was isolated by elective culture. 2. Respiration studies indicate that the nitrile, after degradation to benzoate, is catabolized via catechol or alternatively via p-hydroxybenzoate and 3,4-dihydroxybenzoate. 3. Cell-free extracts of benzonitrile-grown cells contain an enzyme mediating the conversion of benzonitrile into benzoate and ammonia. 4. The nitrilase enzyme was purified by DEAE-cellulose chromatography, (NH4)2SO4 precipitation and gel filtration on Sephadex G-200. The homogeneity of the purified enzyme preparation was confirmed by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and isoelectric focusing on polyacrylamide gel. 5. The enzyme showed a broad pH optimum between pH7.8 and 9.1 and a Km with benzonitrile as substrate of 0.039mm. The activation energy of the reaction deduced from an Arrhenius plot was 48.4kJ/mol. 6. The enzyme was susceptible to inhibition by thiol-specific reagents and certain heavy metal ions. 7. Gel filtration gave a value of 620000 for the molecular weight of the intact enzyme. Sodium dodecyl sulphate/polyacrylamide-gel electrophoresis demonstrated that the enzyme was composed of eight subunits of mol.wt. 76000. 8. Rates of enzymic attack on various substrates indicated that the nitrilase has a fairly broad specificity and that the fungus probably plays an important role in the biodegradation of certain nitrilic herbicides in the environment.


1981 ◽  
Vol 59 (4) ◽  
pp. 301-306 ◽  
Author(s):  
M. George Cherian ◽  
Sharon Yu ◽  
Colvin M. Redman

Free and membrane-attached polysomes were isolated from the livers of normal and cadmium-treated rats, and were translated using L-[35S]cysteine and a nuclease-treated reticulocyte lysate system. The translation products were analyzed for radioactive metallothionein by immunoprecipitation with antibodies to rat cadmium metallothionein followed by sodium dodecyl sulfate – polyacrylamide gel electrophoresis. In both normal and cadmium-treated rats, radioactive metallothionein was produced by free polysomes but not by membrane-attached polysomes. Cadmium treatment did not increase the in vitro ability of polysomes to synthesize metallothionein. As a control, the translation products of these two classes of polysomes were also analyzed for radioactive albumin and it was confirmed that membrane-attached polysomes produce albumin but do not synthesize metallothionein. The cell-free synthesis of metallothionein by free polysomes was also demonstrated by isolation of nascent metallothionein by Sephadex gel filtration and DEAE-cellulose chromatography. In adult rat liver there are two forms of metallothionein and both were produced in vitro by free polysomes.


1974 ◽  
Vol 138 (3) ◽  
pp. 395-405 ◽  
Author(s):  
Roger T. Dean

1. β-Glucuronidase (EC 3.2.1.31) was purified from rabbit liver by a procedure involving autolysis, (NH4)2SO4 fractionation, chromatography on DEAE-cellulose and hydroxyapatite, gel filtration, sedimentation in a sucrose gradient, and isoelectric focusing. 2. Electron microscopy revealed ferritin as the major contaminant in later stages of purification and also showed aggregates of enzyme molecules. Particular attention was paid to the removal of ferritin. 3. The purified enzyme was homogeneous in polyacrylamide-gel electrophoresis both in non-dissociating conditions and in the presence of sodium dodecyl sulphate, and in Ouchterlony gel diffusion and immunoelectrophoresis against polyspecific antisera. 4. Sedimentation in sucrose gradients gave a molecular weight of 300000, whereas gel filtration indicated 440000. 5. Subunits of 75000 molecular weight were observed in gel electrophoresis in the presence of sodium dodecyl sulphate and in gel filtration in the presence of urea. 6. The Km value for p-nitrophenyl β-d-glucuronide was 0.6mm, and the enzyme was extremely sensitive to lactone inhibitors. It was also inhibited by Hg2+ ions. 7. Multiple forms were observed in the pure enzyme by isoelectric focusing, with pI values of 4.5–5.8. Subunits showed similar heterogeneity. The origin of the multiple forms was investigated in detail, and the possibility of artifact generation largely excluded. Some of the forms of lowest pI disappeared after neuraminidase digestion. The nature of the residual heterogeneity remains to be elucidated.


1981 ◽  
Vol 197 (3) ◽  
pp. 629-636 ◽  
Author(s):  
J L McKenzie ◽  
A K Allen ◽  
J W Fabre

Human and canine brain Thy-1 antigens were solubilized in deoxycholate and antigen activity was followed both by conventional absorbed anti-brain xenosera of proven specificity and by mouse monoclonal antibodies to canine and human Thy-1. It is shown that greater than 80% of Thy-1 activity in the dog and man binds to lentil lectin, that the mobility on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis of canine and human Thy-1 is identical with that of rat Thy-1 and that the Stokes radius in deoxycholate of canine and human brain Thy-1 is 3.0 nm and 3.25 nm respectively. Both lentil lectin affinity chromatography followed by gel-filtration chromatography on the one hand and monoclonal antibody affinity chromatography on the other gave high degrees of purification of the brain Thy-1 molecule in the dog and man, resulting in single bands staining for both protein and carbohydrate on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis (except for a slight contaminant of higher molecular weight staining for protein but not carbohydrate with human Thy-1 purified by lentil lectin and gel-filtration chromatography). Analysis of canine and human brain Thy-1 purified by monoclonal antibody affinity chromatography with additional gel filtration through Sephadex G-200 showed that these molecules had respectively 38% and 36% carbohydrate. The amino acid and carbohydrate compositions were similar to those previously reported for Thy-1 of the rat and mouse, the main point of interest being the presence in canine and human brain Thy-1 of N-acetylgalactosamine, which has been reported in rat and mouse brain Thy-1 but not in Thy-1 from other tissues.


1984 ◽  
Vol 219 (3) ◽  
pp. 1009-1015 ◽  
Author(s):  
H C Parkes ◽  
J L Stirling ◽  
P Calvo

beta-N-Acetylhexosaminidase from boar epididymis was separated into two forms, A and B, on DEAE-cellulose. Both these forms were excluded from Sepharose S-200 and had apparent Mr values of 510 000 on gradient gel electrophoresis under non-denaturing conditions. Affinity chromatography on 2-acetamido-N-(6-aminohexanoyl)-2-deoxy-beta-D-glucopyranosylam ine coupled to CNBr-activated Sepharose 4B was used to separate and purify beta-N-acetylhexosaminidases A and B that had specific activities of 115 and 380 mumol/min per mg of protein respectively. Sodium dodecyl sulphate/polyacrylamide-gel electrophoresis of denatured beta-N-acetylhexosaminidase A gave a single major component of Mr 67 000. beta-N-Acetylhexosaminidase B also had this component, and in addition had polypeptides of Mr 29 000 and 26 000. All these polypeptides were glycosylated. Antiserum to the B form precipitated form A from solution and reacted with the 67 000-Mr component or form A after electrophoretic transfer from sodium dodecyl sulphate/polyacrylamide gels to nitrocellulose sheets. The 67 000-Mr components of forms A and B yielded identical peptide maps when digested with Staphylococcus aureus V8 proteinase, and the 29 000-Mr and 26 000-Mr components in form B may be related to the 67 000-Mr polypeptide.


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