scholarly journals Cystatin, a protein inhibitor of cysteine proteinases. Improved purification from egg white, characterization, and detection in chicken serum

1983 ◽  
Vol 211 (1) ◽  
pp. 129-138 ◽  
Author(s):  
A Anastasi ◽  
M A Brown ◽  
A A Kembhavi ◽  
M J H Nicklin ◽  
C A Sayers ◽  
...  

The protein from chicken egg white that inhibits cysteine proteinases, and has been named ‘cystatin’, was purified by ovomucin precipitation, affinity chromatography on carboxymethylpapain-Sepharose and chromatofocusing. The final purification step separated two major forms of the protein (pI 6.5 and 5.6), with a total recovery of about 20% from egg white. By use of affinity chromatography and immunodiffusion it was shown that the inhibitor is also present at low concentrations in the serum of male and female chickens. Tryptic peptide maps of the separated forms 1 and 2 of egg-white cystatin were closely similar, and each form had the N-terminal sequence Ser-Glx-Asx. The two forms showed complete immunological identity, and neither contained carbohydrate. Ki values for the inhibition of cysteine proteinases were as follows: papain (less than 1 × 10(-11)M), cathepsin B (8 × 10(-10)M), cathepsin H (about 2 × 10(-8)M) and cathepsin L (about 3 × 10(-12)M). Some other cysteine proteinases, and several non-cysteine proteinases, were found not to be significantly inhibited by cystatin. The inhibition of the exopeptidase dipeptidyl peptidase I by cystatin was confirmed and the Ki found to be 2 × 10(-10)M. Inhibitor complexes with active cysteine proteinases and the inactive derivatives formed by treatment with iodoacetate, E-64 [L-trans-epoxysuccinylleucylamido(4-guanidino)butane] and benzyloxycarbonylphenylalanylalanyldiazomethane were demonstrated by isoelectric focusing and cation-exchange chromatography. The complexes dissociated in sodium dodecyl sulphate/polyacrylamide-gel electrophoresis (with or without reduction) with no sign of fragmentation of the inhibitor. Cystatin was found not to contain a free thiol group, and there was no indication that disulphide exchange plays any part in the mechanism of inhibition.

1984 ◽  
Vol 223 (1) ◽  
pp. 245-253 ◽  
Author(s):  
M J H Nicklin ◽  
A J Barrett

The interactions between egg-white cystatin and the cysteine proteinases papain, human cathepsin B and bovine dipeptidyl peptidase I were studied. Cystatin was shown to be a competitive reversible inhibitor of cathepsin B (Ki 1.7 nM, k-1 about 2.3×10(-3) s-1). The inhibition of dipeptidyl peptidase I was shown to be reversible (Ki(app.) 0.22 nM, k-1 about 2.2×10(-3) s-1). Cystatin bound papain too tightly for Ki to be determined, but an upper limit of 5 pM was estimated. The association was a second-order process, with k+1 1.0×10(7) M-1×s-1. Papain was shown to form equimolar complexes with cystatin. Sodium dodecyl sulphate/polyacrylamide-gel electrophoresis of complexes formed between papain or cathepsin B and an excess of cystatin showed no peptide bond cleavage after incubation for 72 h. The reaction of the active-site thiol group of papain with 5,5′-dithiobis-(2-nitrobenzoic acid) at pH 8 and 2,2′-dithiobispyridine at pH 4 was blocked by complex-formation. Dipeptidyl peptidase I and papain were found to compete for binding to cystatin, contrary to a previous report. The two major isoelectric forms of cystatin were found to have similar specific inhibitory activities for papain, and similar affinities for papain, cathepsin B and dipeptidyl peptidase I. This, together with specific oxidation of the N-terminal serine residue with periodate, showed the N-terminal amino group of cystatin 1 to be unimportant for inhibition. General citraconylation of amino groups resulted in a large decrease in the affinity of cystatin for dipeptidyl peptidase I. It is concluded that the interaction of cystatin with cysteine proteinases has many characteristics similar to those of an inhibitor such as aprotinin with serine proteinases.


1978 ◽  
Vol 39 (03) ◽  
pp. 616-563 ◽  
Author(s):  
Inge Clemmensen

SummaryHuman antithrombin III was purified from fresh human plasma by affinity chromatography on heparin-Sepharose®, affinity chromatography on concanavalin A Sepharose®, gel filtration on Ultrogel® AcA 34, ion exchange chromatography on DEAE A-50 Sephadex® and preparative agarose gel electrophoresis. The hydrolytic activity of urokinase (plasminogen activator from urine) on acetyl-glycyl-L-lysine methyl ester acetate (Ac-gly-lys-OMe Ac) was inhibited by antithrombin III in a slow time-dependent manner. Heparin accelerated the reaction between activator and inhibitor. Inhibition of catalytic activity was associated with the formation of an 1:1 molar complex between activator and inhibitor as revealed by sodium dodecyl sulphate polyacrylamide gel electrophoresis. The complex was also demonstrated by crossed Immunoelectrophoresis against anti-antithrombin III.


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.


1985 ◽  
Vol 63 (9) ◽  
pp. 932-940 ◽  
Author(s):  
Gilles Dupuis ◽  
Jean-Pierre Doucet ◽  
Bânû Bastin ◽  
Jeannine Cardin

We describe the isolation of pig spleen lymphocyte glycoproteins that interact with phytohemagglutinin (PHA), the lectin from Phaseolus vulgaris. Purification was achieved by affinity chromatography of a Nonidet P-40 extract of the cells on a PHA – Affi-Gel 10 column. The retained glycoproteins were eluted with an acidic (pH 3.0) glycine buffer and represented 1.9–2.4% of the amount of protein applied to the column. They contained 20 ± 1.3% hexose and 1.7 ± 0.7% fatty acids, on a weight basis. Electrophoretic analyses (sodium dodecyl sulfate – polyacrylamide gel electrophoresis) showed the presence of major Coomassie blue positive bands with apparent molecular masses of 50–55, 75, 95, 130, and 155 kdaltons along with minor bands of 20–40, 42, 45, 60–65, 175, and 200–250 kdaltons. The purified PHA-receptor glycoproteins inhibited, in a dose-dependent manner, the incorporation of [3H]thymidine in pig lymphocytes cultured at a concentration of 106 cells/mL in the presence of PHA. A 50% inhibition was observed when 20 μg/mL of the glycoproteins was added to the lymphocyte cultures containing 0.5 μg/mL of PHA. Scatchard analysis of the binding of 125I-labelled PHA, in the presence of increasing amounts of the purified glycoproteins, showed a suppression of the binding of the lectin to high affinity sites of the cells, as evidenced by a change from biphasic to a linear profile. Results of binding suggested a competitive inhibition by a population of purified glycoproteins with a similar affinity for the lectin. The purified glycoproteins decreased PHA-dependent interleukin 2 (IL-2) production by pig lymphocytes as assayed with a IL-2 dependent murine cell line. It is suggested that the affinity-purified PHA-reactive glycoproteins are inhibitors of PHA-dependent cellular responses because they compete with PHA-receptor sites on the lymphocyte plasma membrane. A mouse antiserum raised against the purified glycoproteins inhibited PHA-induced lymphocyte activation, but did not stimulate lymphocytes when added alone to lymphocyte cultures or in combination with a antimouse antiserum.


2021 ◽  
Vol 13 (2) ◽  
pp. 107-112
Author(s):  
C.F. Okechukwu ◽  
P.L. Shamsudeen ◽  
R.K. Bala ◽  
B.G. Kurfi ◽  
A.M. Abdulazeez

The most effective and acceptable therapy for snakebite victims is the immediate administration of antivenin which is limited by problems of hypersensitivity reactions in some individuals and its inability to resolve the local effects of the venom. The aim of this study was to isolate, partially purify and characterize phospholipase A2 from Naja Katiensis venom. Phospholipase A2 was partially purified via a two-step process: gel filtration on Sephadex G-75 and ion exchange chromatography using CM Sephadex, and subjected to SDS-PAGE analysis. From the results, the specific activity of the partially purified PLA2 decreased from 0.67μmol/min/mg in crude venom to 0.29μmol/min/mg after ion exchange chromatography with a yield of 5% and purification fold of 0.43. The optimum temperature of the purified PLA2 was found to be 35ºC and optimum p.H of 7. velocity studies for the determination of kinetic constants using L-a-lecithin as substrate revealed a Km  of 1.47mg/ml and Vmax  of 3.32μ moles/min/mg. The sodium dodecyl sulphate polyacrylamide gel electrophoresis of the purified PLA2 showed a distinct band with molecular weight estimated to be 14KDa. In conclusion, the present study shows that phospholipase A2 was isolated, purified and characterized. This may serve as a promising candidate for future development of a novel anti-venin drug.


2019 ◽  
Vol 12 (1) ◽  
pp. 68-73
Author(s):  
Questan Amin ◽  
Hemn Zhahir ◽  
Ahmed Shaker

Proteins are essential constituents of all organisms; both egg white proteins and egg yolk are source of protein. The aim of this study was conducted to perform preliminary studies to analyses and compare egg white proteins and yolk proteins from different avian species (guineafowl, dwarf hens, local hen, Shami, turkey, duck, geese, partridge and quail) via or with SDS-PAGE (Sodium Dodecyl Sulfate–Polyacrylamide Gel Electrophoresis ). 18 Fresh eggs of different poultry species (guineafowl, dwarf hens, local hen, Shami, turkey, duck, geese, partridge and quail) were collected from various farms in the Sulaimani province. Data on egg proteins were analyzed using Statistical Xlstate used for dendrogram construction and PCA. The main egg white proteins were Ovomicin, Ovotransferrin, Ovalbumin, Flavoprotein, α- chymotrypsinogen, and Trypsin inhibitor. The main lipoproteins were Apovitellenin VI, Apovitellenin Vb, Apovitellenin V, Apovitellenin IIIa, Apovitellenin III, Apovitellin 7, B-Livetin, Apovitellenin IIa, Apovitellenin II, and Apovitellenin I. All these lipoproteins were observed in the nine birds species. The egg white proteins and yolk lipoproteins for nine species were examined. It can be concluded the large differences were found in a mount of egg white proteins and yolk lipoproteins of the nine species of birds.


1980 ◽  
Vol 192 (1) ◽  
pp. 9-18 ◽  
Author(s):  
I R Cottingham ◽  
C I Ragan

L-3-Glycerophosphate dehydrogenase (EC 1.1.99.5) was purified from pig brain mitochondria by extraction with deoxycholate, ion-exchange chromatography and (NH4)2SO4 fractionation in cholate, and preparative isoelectric focusing in Triton X-100. Sodium dodecyl sulphate/polyacrylamide gel electrophoresis shows that the purified enzyme consists of a single subunit of mol.wt. 75 000. The enzyme contains non-covalently bound FAD and low concentrations of iron and acid labile sulphide. No substrate reducible e.p.r. signals were detected. The conditions of purification, particularly the isoelectric focusing step, lead to considerable loss of FAD and possibly iron-sulphur centres. It is therefore not possible to decide with certainty whether the enzyme is a flavoprotein or a ferroflavoprotein. The enzyme catalyses the oxidation of L-3-glycerophosphate by a variety of electron acceptors, including ubiquinone analogues. A number if compounds known to inhibit ubiquinone oxidoreduction by other enzymes of the respiratory chain failed to inhibit L-3-glycerophosphate dehydrogenase, except at very high concentrations.


1978 ◽  
Vol 173 (2) ◽  
pp. 633-641 ◽  
Author(s):  
R K Craig ◽  
D McIlreavy ◽  
R L Hall

1. Guinea-pig caseins A, B and C were purified free of each other by a combination of ion-exchange chromatography and gel filtration. 2. Determination of the amino acid composition showed all three caseins to contain a high proportion of proline and glutamic acid, but no cysteine. This apart, the amino acid composition of the three caseins was markedly different, though calculated divergence values suggest that some homology may exist between caseins A and B. Molecular-weight estimates based on amino acid composition were in good agreement with those based on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. 3. N-Terminal analysis showed lysine, methionine and lysine to be the N-terminal residues of caseins A, B and C respectively. 4. Two-dimensional separation of tryptic digests revealed a distinctive pattern for each casein. 5. All caseins were shown to be phosphoproteins. The casein C preparation also contained significant amounts of sialic acid, neutral and amino sugars. 6. The results suggest that each casein represents a separate gene product, and that the low-molecular-weight proteins are not the result of a post-translational cleavage of the largest. All were distinctly different from the whey protein alpha-lactalbumin.


1997 ◽  
Vol 9 (4) ◽  
pp. 475 ◽  
Author(s):  
James R. McFarlane ◽  
Carl D. Rudd ◽  
Lynda M. Foulds ◽  
Terry P. Fletcher ◽  
Marilyn B. Renfree

Tammar wallaby (Macropus eugenii) luteinizing hormone (LH) was purified from pituitaries collected from wild and captive populations by salt sequential precipitation, ion exchange chromatography and gel filtration. Pituitary tissue (5 g) yielded 1·8 mg of purified wallaby luteinizing hormone (ME-14B), as verified by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). A heterologous radioimmunoassay has been developed for measurement of LH in plasma of marsupials using a monoclonal antibody raised against bovine LH (518B7). This assay system was able to measure basal LH concentrations in male and female tammars and detected a significant rise in plasma LH in response to oestradiol benzoate in female tammars and luteinizing hormone-releasing hormone (LHRH) in males. Parallel dose–response curves were also obtained from pituitary extracts from four other species of marsupial (brushtail possum, Trichosurus vulpecula; brown antechinus,Antechinus stuartii; kowari, Dasyuroides byrnei; and Eastern pygmy possum,Cercartetus nanus) in this assay, which suggests its usefulness in the measurement of LH in other marsupial species.


Blood ◽  
1993 ◽  
Vol 82 (11) ◽  
pp. 3343-3349 ◽  
Author(s):  
PC Simons ◽  
L Elias

Abstract This laboratory has been characterizing protein serine/threonine kinase reactions of hematopoietic tissues, whose most distinguishing characteristics in vitro are stimulation with vesicular phosphatidyl glycerol, and the ability to function using Mn2+ as the sole divalent cation. The major protein substrates are a 73-kD protein and a protein migrating near ovalbumin on sodium dodecyl sulfate polyacrylamide gel electrophoresis. The 47-kD protein was partially purified from cells harvested by leukapheresis from a patient with acute myelogenous leukemia, using ammonium sulfate precipitation and ion exchange chromatography. This partially purified ion-exchange fraction contained an endogenous kinase activity with characteristics similar to those we previously described of protein kinase P (protein kinase, phospholipid- stimulable: PK-P), but not typical of any form of protein kinase C (PK- C). With longer phosphorylation, the 47-kD band showed increasingly lower mobility demonstrable both by Coomassie blue staining and autoradiography, suggesting both that it was multiply phosphorylated, and that the excisable band was pure. The protein was thus eluted from preparative gel slices and digested with endoproteinase lys C. Sequence data from the fragments identified the protein as the 47-kD calpain fragment of talin, a protein found in focal adhesion plaques and some cell-cell contacts. PK-C phosphorylated the 47-kD protein, as has been reported previously, and phosphopeptide mapping disclosed a similar pattern of phosphorylation using either PK-C or the endogenous activity. The 47-kD protein labeled with the endogenous kinase contained predominantly phosphoserine, with some phosphothreonine and a trace of phosphotyrosine. Intact, purified talin was also phosphorylated by PK-P in a phospholipid-stimulable manner, but at 1/20 the rate of the 47-kD fragment.


Sign in / Sign up

Export Citation Format

Share Document