scholarly journals Inhibition of cysteine proteinases and dipeptidyl peptidase I by egg-white cystatin

1984 ◽  
Vol 223 (1) ◽  
pp. 245-253 ◽  
Author(s):  
M J H Nicklin ◽  
A J Barrett
Keyword(s):  
Cathepsin B ◽  
Bond Cleavage ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Dipeptidyl Peptidase ◽  
Egg White ◽  
Reversible Inhibitor ◽  
Cysteine Proteinases ◽  
Peptide Bond Cleavage ◽  
Specific Oxidation

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.

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 ◽  
...  
Keyword(s):  
Affinity Chromatography ◽  
Cathepsin L ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Thiol Group ◽  
Egg White ◽  
Exchange Chromatography ◽  
Cysteine Proteinases ◽  
Total Recovery ◽  
Free Thiol Group

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.

scholarly journals Variation of egg proteins between bird varieties by using SDS-PAGE

2019 ◽  
Vol 12 (1) ◽  
pp. 68-73
Author(s):  
Questan Amin ◽  
Hemn Zhahir ◽  
Ahmed Shaker
Keyword(s):  
Sodium Dodecyl Sulfate ◽  
Trypsin Inhibitor ◽  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Egg Yolk ◽  
Egg White ◽  
Yolk Proteins ◽  
Egg White Proteins ◽  
Sds Page

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.

Studies of human pituitary LH containing internally cleaved β subunit

1991 ◽  
Vol 6 (1) ◽  
pp. 101-109 ◽  
Author(s):  
A. Stockell Hartree ◽  
R. C. Shownkeen
Keyword(s):  
Receptor Binding ◽  
Proteolytic Enzyme ◽  
Enzyme Inhibitor ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Peptide Bond ◽  
Β Subunit ◽  
Human Pituitary ◽  
Α Subunit ◽  
Peptide Bond Cleavage

ABSTRACT We have investigated the origin of the internal peptide bond cleavage found in the β subunit of a proportion of pituitary human LH (hLH) molecules, as well as the effects of this cleavage (or nick) on the interaction between α and β subunits and on binding of hLH to its receptor. The content of cleaved β subunit, assessed by the intensity of staining of an approximately 10 kDa component on sodium dodecyl sulphate-polyacrylamide gel electrophoresis of reduced hLH, was variable in batches of hLH prepared from pooled acetone-preserved human pituitary glands. There was evidence of a similar cleavage in purified hTSH, but not in the purified hFSH or human chorionic gonadotrophin examined. Although intact hLH was relatively resistant to cleavage in solution, urea dissociation of hormone followed by dialysis resulted in an increased content of nicked β subunit, which was largely prevented by incorporation of the proteolytic enzyme inhibitor phenylmethylsulphonyl fluoride (PMSF) and the metal-chelating agent EDTA. Hormone that was virtually free of nicked β subunit was obtained by urea dissociation of hLH subunits in the presence of PMSF and EDTA followed by dialysis to remove urea, reassociation of subunits at 37 °C (pH 7) and purification of reassociated hLH dimer by gel filtration on Sephadex G-100 in the presence of 1-anilinonaphthalene-8-sulphonic acid (ANS). When hLH was incubated at 37 °C at pH 55 or pH 95 in the absence of enzyme inhibitors, some cleaved β subunit was found in the hLH—ANS dimer form of the hormone, but most of the nicked subunit appeared in fractions of lower molecular weight and with low receptor-binding activity. Fractions isolated as hLH—ANS dimer had receptor-binding activities which were negatively correlated with their content of cleaved β subunit, the most active fraction (21 000 i.u./mg) being virtually free of this component. Our studies suggest (1) that the cleavage is caused by proteolytic enzyme activity present in human pituitary tissue and in purified preparations of hLH, (2) that free hLH-β subunit is cleaved far more readily than when it is combined with α subunit in the intact hormone, (3) that the presence of the cleavage in free hLH-β prevents refolding of this subunit to the correct conformation that permits its combination with α subunit to regenerate native hormone, and (4) that the site of cleavage is likely to be at a peptide bond located on the surface of the intact hLH molecule.

scholarly journals Reutilization of Food Waste: One-Step Extration, Purification and Characterization of Ovalbumin from Salted Egg White by Aqueous Two-Phase Flotation

Foods ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 286 ◽  
Author(s):  
Bin Jiang ◽  
Jiaxin Na ◽  
Lele Wang ◽  
Dongmei Li ◽  
Chunhong Liu ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Flow Rate ◽  
High Performance ◽  
Binding Capacity ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Egg White ◽  
Two Phase ◽  
One Step ◽  
Egg Yolks

For the purpose of reducing pollution and the reutilization of salted egg whites, which are byproducts of the manufacturing process of salted egg yolks and normally treated as waste, an aqueous two-phase flotation (ATPF) composed of polyethylene glycols (PEG 1000) and (NH4)2SO4 was applied to develop a simple, inexpensive and efficient process for the separation of ovalbumin (OVA) from salted egg whites. The effects of the concentration of PEG, the concentration of (NH4)2SO4, the flow rate and the flotation time on the flotation efficiency (Y) and purity (P) of OVA were investigated. A response surface method (RSM) experiment was carried out on the basis of a single-factor experiment. An efficient separation was achieved using ATPF containing 5 mL of 80% PEG 1000 (w/w), 28 mL of 28% (NH4)2SO4 (w/w), 35 mL/min of the flow rate and 30 min of the flotation time, while 2 mL of the salted egg white solution (salted eggs white (v): water (v) = 1:4) was loaded. Under the optimal conditions, Y and P of OVA could reach 82.15 ± 0.24% and 92.98 ± 0.68%, respectively. The purified OVA was characterized by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), reverse phase high-performance liquid chromatography (RP-HPLC), liquid chromatography-nano electrospray ionisation mass spectrometry (Nano LC-ESI-MS/MS), ultraviolet spectrum (UV), fluorescence spectrum (FL) and fourier transform infrared spectroscopy (FT-IR). The results indicated that the purity of OVA obtained by ATPF was satisfactory and there was no obvious difference in the structure of the OVA separated by ATPF and the standard. The results of the functional properties revealed no significant differences between OVA obtained by ATPF and the standard in oil binding capacity, viscosity, emulsibility and foam capacity.

A novel metalloproteinase present in freshly isolated rat glomeruli

1991 ◽  
Vol 260 (4) ◽  
pp. F555-F561 ◽  
Author(s):  
Q. Le ◽  
S. Shah ◽  
H. Nguyen ◽  
S. Cortez ◽  
W. Baricos
Keyword(s):  
Gel Electrophoresis ◽  
Mesangial Cells ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Significant Inhibition ◽  
Tissue Inhibitors Of Metalloproteinases ◽  
Cysteine Proteinases ◽  
Ph Optimum ◽  
Major Band ◽  
Isolated Rat

We have utilized [3H] gelatin to document high activity of a metalloproteinase present in freshly isolated rat glomeruli. [3H] gelatin degradation by glomeruli was markedly inhibited by EDTA (10 mM: -89 +/- 2.3%) and o-phenanthroline (2 mM: -72 +/- 0.1%), inhibitors of metalloproteinases. No significant inhibition of [3H]gelatin degradation was observed with inhibitors of serine or cysteine proteinases. Most (greater than 80%) of the glomerular metalloproteinase (GLOMP) activity was associated with the pellet after centrifugation of sonicated glomeruli at 100,000 g for 90 min. The pH optimum for gelatin degradation by sonicated glomeruli was approximately pH 8.5. Sodium dodecyl sulfate substrate (gelatin)-polyacrylamide gel electrophoresis revealed a single major band of EDTA-inhibitable gelatin-degrading activity with a molecular mass of approximately 116-125 kDa. The GLOMP activity was not inhibited by tissue inhibitors of metalloproteinases, did not appear to be latent, and was not activated by organomercurial activators of several latent metalloproteinases. GLOMP activity was increased 3.4-fold after incubation with trypsin (20 micrograms/ml, 25 min, 22 degrees C). These data indicate that GLOMP is distinct from the previously described matrix metalloproteinases, as well as other metalloproteinases present in the kidney, including the gelatinase secreted by cultured mesangial cells, Meprin, and endopeptidase 24.11 (enkephalinase, EC 3.4.24.11).

scholarly journals Interrelationship of active and latent secreted human cathepsin B precursors

1986 ◽  
Vol 233 (1) ◽  
pp. 57-63 ◽  
Author(s):  
J S Mort ◽  
A D Recklies
Keyword(s):  
Cathepsin B ◽  
Polyacrylamide Gel Electrophoresis ◽  
Active Form ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
Molecular Size ◽  
Alkaline Ph ◽  
Endopeptidase Activity ◽  
Alkali Stability ◽  
Lysosomal Proteinase

Two high-Mr forms of cathepsin B have been described previously, both of which are stable at alkaline pH, in contrast with the lysosomal proteinase. One form is latent and activated by pepsin treatment; the other form is active as measured with synthetic substrates. In the present study it was shown that the two forms are indistinguishable on the basis of molecular size as determined by gel-filtration chromatography or sodium dodecyl sulphate/polyacrylamide-gel electrophoresis followed by immunoblotting. Both forms lose their alkali-stability upon exposure to Hg2+, and after Hg2+ treatment the latent form becomes immuneprecipitable by an antiserum that reacts only with denatured cathepsin B. Lysosomal cathepsin B is bound by the plasma proteinase inhibitor alpha 2-macroglobulin, a process that requires proteolytic cleavage of the inhibitor. In contrast, the stable active form of cathepsin B is not bound by this inhibitor unless this enzyme is first destabilized by Hg2+ treatment. These results indicate that cathepsin B exists in three different states of activity, completely latent, partially active and fully proteolytically active. To exhibit true endopeptidase activity it seems that the enzyme must be in an alkali-unstable form.

Limited proteolysis of rabbit cardiac procathepsin D in a cell-free system

1986 ◽  
Vol 250 (4) ◽  
pp. C589-C596 ◽  
Author(s):  
A. M. Smarel ◽  
S. W. Worobec ◽  
A. G. Ferguson ◽  
R. S. Decker ◽  
M. Lesch
Keyword(s):  
Cathepsin B ◽  
Cathepsin D ◽  
Intracellular Transport ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Limited Proteolysis ◽  
Cysteine Proteases ◽  
Proteolytic Processing ◽  
Reaction Products ◽  
Free System

Rabbit cardiac cathepsin D is initially synthesized as an inactive, apparent molecular weight (Mr) 53,000, pI 6.6 precursor (procathepsin D) that is proteolytically processed during intracellular transport to produce the Mr 48,000 isoforms of active cathepsin D found in cardiac lysosomes. To examine potential proteases responsible for intracellular proteolytic processing, biosynthetically labeled procathepsin D was isolated from rabbit ventricular tissue perfused for 30 min with [35S]methionine. Procathepsin D was then incubated in vitro (40 degrees C, 1-240 min) with active cathepsin D, papain, and cathepsin B, either singly or sequentially, and the reaction products analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and two-dimensional electrophoresis. Incubation of 35S-labeled procathepsin D with active cathepsin D produced a single reaction product (Mr 51,000; pI 6.2). This limited proteolysis occurred at pH 3-5 and was inhibited by pepstatin. Incubation of 35S-labeled procathepsin D with papain or cathepsin B produced a major reaction product (Mr 48,000; pI 6.4) and a minor form (Mr 50,000; pI 6.0). These reactions occurred at pH 4-7 and were inhibited by leupeptin but not pepstatin. Only the Mr 48,000, pI 6.4 products of papain and cathepsin B-mediated proteolysis comigrated with the most basic isoform of active cathepsin D found in cardiac tissue. In addition, the Mr 51,000 intermediate produced by cathepsin D was susceptible to further limited proteolysis by cysteine proteases with resultant production of a Mr 48,000 product. Thus the intracellular proteolytic processing of rabbit cardiac procathepsin D does not result solely from autocatalysis but requires at least one other protease, possibly cathepsin B.

scholarly journals Biosynthesis of collagen and other matrix proteins by articular cartilage in experimental osteoarthrosis

1980 ◽  
Vol 188 (3) ◽  
pp. 823-837 ◽  
Author(s):  
D R Eyre ◽  
C A McDevitt ◽  
M E Billingham ◽  
H Muir
Keyword(s):  
Articular Cartilage ◽  
Bond Cleavage ◽  
Gradient Centrifugation ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Dry Weight ◽  
Type Ii Collagen ◽  
Protein Band ◽  
The Matrix

Osteoarthrosis was induced in one knee joint of dogs by an established surgical procedure. Changes in the articular cartilage in the biosynthesis of collagen and other proteins were sought by radiochemical labelling in vivo, with the following findings. (1) Collagen synthesis was stimulated in all cartilage surfaces of the experimental joints at 2, 8 and 24 weeks after surgery. Systemic labelling with [3H]proline showed that over 10 times more collagen was being deposited per dry weight of experimental cartilage compared with control cartilage in the unoperated knee. (2) Type-II collagen was the radiolabelled product in all samples of experimental cartilage ranging in quality from undamaged to overtly fibrillated, and was the only collagen detected chemically in the matrix of osteoarthrotic cartilage from either dog or human joints. (3) Hydroxylysine glycosylation was examined in the newly synthesized cartilage collagen by labelling dog joints in vivo with [3H]lysine. In experimental knees the new collagen was less glycosylated than in controls. However, no difference in glycosylation of the total collagen in the tissues was observed by chemical analysis. (4) Over half the protein-bound tritium was extracted by 4 M-guanidinium chloride from control cartilage labelled with [3H]proline, compared with one-quarter or less from experimental cartilage. Two-thirds of the extracted tritium separated in the upper fraction on density-gradient centrifugation in CsCl under associative conditions. Much of this ran with a single protein band on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis under reducing conditions. The identity of this protein was unknown, although it resembled serum albumin in mobility afte disulphide-bond cleavage.

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