scholarly journals Role of thiols in degradation of proteins by cathepsins

1982 ◽  
Vol 204 (2) ◽  
pp. 471-477 ◽  
Author(s):  
T Kooistra ◽  
P C Millard ◽  
J B Lloyd
Keyword(s):  
Cathepsin D ◽  
Limited Proteolysis ◽  
Lysosomal Storage ◽  
Protein Substrates ◽  
Disulphide Bonds ◽  
Protection Method ◽  
Opening Up ◽  
Lysosome Membrane

The effects of thiols on the breakdown of 125I-labelled insulin, albumin and formaldehyde-treated albumin by highly purified rat liver cathepsins B, D, H and L at pH 4.0 and 5.5 were studied. At both pH values degradation was strongly activated by the thiols cysteamine, cysteine, dithiothreitol, glutathione and 2-mercaptoethanol, and its rate increased with increasing thiol concentration. Preincubation of the protein substrates with 5 mM-glutathione did not affect concentration. Preincubation of the protein substrates with 5 mM-glutathione did not affect the rate of degradation by cathepsin D or L, and determination of free thiol groups after incubation of the proteins in the presence of glutathione but without cathepsin showed that their disulphide bonds were stable under the incubation conditions. Sephadex G-75 chromatography of the acid-soluble products of insulin digestion by cathepsin D or L suggested that thiols can reduce disulphide bonds in proteins after limited proteolysis. The resultant opening-up of the protein structure would lead to further proteolysis, so that the two processes (proteolysis and reduction) may act synergistically. By using the osmotic protection method it was shown that, at a physiological pH, cysteamine, and its oxidized form cystamine, can cross the lysosome membrane and thus may well be the physiological hydrogen donor for the reduction of disulphides in lysosomes. The results are discussed in relation to the lysosomal storage disease cystinosis.

“Put Yourself in Her Shoes”

2017 ◽  
Author(s):  
Jennifer N. Fish
Keyword(s):  
Human Rights ◽  
Civil Society ◽  
Domestic Workers ◽  
The State ◽  
Cross Sectional ◽  
Government Influence ◽  
Opening Up

This chapter looks at the role of NGOs, global and national unions, and feminist government leaders in the movement to support domestic workers’ global rights. Here, the merger of civil society activism, labor struggles, and government influence reveals how a cross-sectional range of players served in pivotal roles as allies in the determination of policy protections. Relations between domestic workers and the state are analyzed to show the potential for opening up new spaces of worker activism. The discussion of feminist government leaders, or femocrats, reveals how the unexpected alliance of women in positions of power and women in some of the world’s most marginalized positions resulted in a synergy that shook a staid, bureaucratic institution to its core, and enabled its reorientation to more effectively address issues of global human rights.

scholarly journals Role of thiols, pH and cathepsin D in the lysosomal catabolism of serum albumin

1984 ◽  
Vol 218 (3) ◽  
pp. 775-783 ◽  
Author(s):  
J L Mego
Keyword(s):  
Serum Albumin ◽  
Cathepsin D ◽  
Proteinase Inhibitors ◽  
Disulphide Bond ◽  
Ph Optimum ◽  
Protein Substrates ◽  
Low Concentrations ◽  
Liver And Kidney ◽  
Thiol Proteinases

Attempts were made to assess the role of thiols and to determine the cathepsins involved in the degradation of serum albumin in mouse liver and kidney lysosomes. Unlike cysteine or beta-mercaptoethanol, reduced glutathione (GSH) did not stimulate the degradation of formaldehyde-treated albumin in liver lysosomes, suggesting that the tripeptide did not penetrate the membrane. However, GSH was a much more effective stimulant of proteolysis in kidney lysosomes than was cysteine at low concentrations, and the effect was saturable at 1-2 mM concentrations. Thiols did not stimulate proteolysis in lysosomes when the disulphide bonds of albumin were reduced and alkylated, suggesting that the stimulatory effects were solely due to disulphide-bond reduction in protein substrates. Results obtained with thiols and iodoacetamide suggested that albumins denatured by disulphide-bond reduction and alkylation, disulphide-bond reduction without alkylation, or by treatment with 8 M-urea, were all degraded primarily by cathepsin D in lysosomes, but formaldehyde-denatured albumin was attacked by thiol proteinases. These findings correlated well with studies on the degradation of these proteins by rat liver lysosome (tritosome) extracts. Studies with the proteinase inhibitors leupeptin and pepstatin and the stimulatory effects of thiols in these extracts suggested that formaldehyde-denatured albumin was degraded primarily by the thiol proteinases, but that native albumin or albumins denatured by disulphide-bond reduction or by treatment with 8 M-urea were attacked by cathepsin D. Denaturation of serum albumin by any of the methods used caused a shift in the pH optimum of albumin catabolism by tritosome extracts or by purified cathepsin D from approx. 3-4 to 5-6. These results were discussed in terms of a possible mechanism for the catabolic aspect of serum albumin turnover.

scholarly journals BREAST CANCER

2006 ◽  
Vol 13 (03) ◽  
pp. 338-340
Author(s):  
MUMTAZ BEGUM ◽  
GHAZALA RUBY ◽  
RUKHASHAN KHURSHID ◽  
Saleem Akhtar
Keyword(s):  
Breast Cancer ◽  
Tumor Marker ◽  
Cancer Patients ◽  
Immunoglobulin G ◽  
Cathepsin D ◽  
Stage Iii ◽  
Ca 15.3 ◽  
Significant Difference

CA 15.3 is a useful parameter in the management of patients in different stages ofthe breast cancer. Objectives: (1) To evaluate the level of CA 15-3 in stage III carcinoma of breast. (2) To study therole of immunoglobulin G and cathepsin D. Patients & Methods: Serum CA 15-3 was assayed in a group of 25 femalebreast cancer patients with stage III. Method used for determination of CA 15-3 is IMMULITE Automated ImmunoassaySystem. Result: 25 patients were taken in the study. It was observed that the level of CA 15-3 and cathepsin D issignificantly increased in patients as compared to control subjects. Although the level of IgG was also increased butit shows no significant difference. Conclusion: It is concluded that CA 15-3 can be used as tumor marker especiallyin the 3 stage rd of breast cancer and also for monitoring the treatment. IgG shows the role of body defense mechanismsystem in breast cancer. Whereas protease like cathepsin D shows the extent of metastasis.

scholarly journals Interaction of human cathepsin D with the inhibitor pepstatin

1976 ◽  
Vol 155 (1) ◽  
pp. 117-125 ◽  
Author(s):  
C G Knight ◽  
A J Barrett
Keyword(s):  
Cathepsin D ◽  
Specific Activity ◽  
Dissociation Constants ◽  
Equilibrium Dialysis ◽  
Tight Binding ◽  
Extinction Coefficients ◽  
Titration Curves ◽  
Human Cathepsin

1. Because of the proposed role of cathepsin D in a variety of biological and pathological processes, the characteristics of inhibition by the potentially useful agent, pepstatin, were determined. 2. The β and γ forms of human cathepsin D, separated by isoelectric focusing, have identical specific extinction coefficients and specific activity in the degradation of haemoglobin. 3. Cathepsin D showed tight binding of 1 mol of pepstatin per 43000 g of protein, indicating that titration with the inhibitor represents a useful method for determination of absolute concentrations of the enzyme. 4. The titration curves were used to determine apparent dissociation constants (KD) for the binding of pepstatin and pepstatin methyl ester at pH3.5; values of approx. 5 } 10(-10)M were obtained. 5. Pepstatinyl-[3H]glycine was synthesized and shown to have a KD similar to that of pepstatin. Gel-chromatographic experiments showed that the binding of pepstatin and its derivatives is strongly pH-dependent. 6. The effect of pH on the KD for pepstatinyl-glycine was determined by equilibrium dialysis. As the pH was raised from 5.0 to 6.4, KD rose from 5 } 10(-10)M to 2 } 10(-6)M. 7. The catalytic activity of cathepsin D declines essentially to zero on going from pH5.0 to pH7.0, and we suggest that the binding site for substrate and pepstatin is abolished by a conformational change in the enzyme molecule. 8. The data indicate that, in biological experiments near neutral pH, large molar excesses of pepstatin over cathepsin D will be required for efficient inhibition.

scholarly journals Structure analysis of purified histone H5 and of H5 in nuclei by limited proteolysis

1992 ◽  
Vol 282 (2) ◽  
pp. 435-441
Author(s):  
M Hallupp ◽  
F Buck ◽  
W H Strätling
Keyword(s):  
Central Region ◽  
Limited Proteolysis ◽  
Structural Features ◽  
Compact Structure ◽  
Core Domain ◽  
Histone H5 ◽  
Unstructured Protein ◽  
Exposed Location

The structure of purified histone H5 in 1 M-NaClO4 and of H5 in nuclei was analysed by digestion with either one of three endoproteinases, papain, subtilisin or elastase, which preferentially cleave unstructured protein regions (and additionally with trypsin). Digestion with papain and subtilisin produced ‘limiting’ resistant peptides (p1 and s1) that contain the central region between residues 18-20 and residue 114. Digestion of purified H5 with elastase generated resistant peptides e1 and e2, and that of H5 in nuclei, peptide e2. Peptides e1 and e2 contain the region from residues 22 to 114 and 109 respectively. These results show that a central region of H5 encompassing the sequence between residues 18-22 and residue 114 is folded into a compact structure. A central structured ‘core’ domain ranging from residues 22 to 100 is defined by the limit trypsin peptide t3, which is identical to the previously described fragment GH5 [Aviles et al. (1978) Eur. J. Biochem. 88, 363-371]. Generation of peptides e2 and t3, as well as of resistant peptides of lower abundance, shows that the sites near Lys-100 and Lys-109 exhibit some proteolytic sensitivity, which may result either from an exposed location or from a locally less compact conformation. Significantly, all these structural features of H5 are manifested in the purified form as well as in nuclei. A role of the structured region from residues 101 to 114 for the interaction with linker DNA and the determination of its path is discussed.

A Molecular Approach to Immunoscintigraphy: A Study of the T-Antigen Conformation on the Surface of Tumors

1987 ◽  
Vol 26 (01) ◽  
pp. 1-6 ◽  
Author(s):  
S. Selvaraj ◽  
M. R. Suresh ◽  
G. McLean ◽  
D. Willans ◽  
C. Turner ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Tumor Cell ◽  
T Antigen ◽  
Human Carcinomas ◽  
Animal Tumor ◽  
Synthetic Antigens

The role of glycoconjugates in tumor cell differentiation has been well documented. We have examined the expression of the two anomers of the Thomsen-Friedenreich antigen on the surface of human, canine and murine tumor cell membranes both in vitro and in vivo. This has been accomplished through the synthesis of the disaccharide terminal residues in both a and ß configuration. Both entities were used to generate murine monoclonal antibodies which recognized the carbohydrate determinants. The determination of fine specificities of these antibodies was effected by means of cellular uptake, immunohistopathology and immunoscintigraphy. Examination of pathological specimens of human and canine tumor tissue indicated that the expressed antigen was in the β configuration. More than 89% of all human carcinomas tested expressed the antigen in the above anomeric form. The combination of synthetic antigens and monoclonal antibodies raised specifically against them provide us with invaluable tools for the study of tumor marker expression in humans and their respective animal tumor models.

On The Mechanism Of Heparin-Induced Potentiation Of Platelet Aggregation

1981 ◽  
Author(s):  
M Yamamoto ◽  
K Watanabe ◽  
Y Ando ◽  
H Iri ◽  
N Fujiyama ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Platelet Activation ◽  
Coagulation Factors ◽  
Marked Enhancement ◽  
Matrix Bound ◽  
Induced Aggregation ◽  
Aggregation Of Platelets ◽  
Plasma Heparin

It has been suggested that heparin caused potentiation of aggregation induced by ADP or epinephrine. The exact mechanism of heparin-induced platelet activation, however, remained unknown. In this paper, we have investigated the role of anti-thrombin III ( AT ) in heparin-induced platelet activation using purified AT and AT depleted plasma. When ADP or epinephrine was added to citrated PRP one minute after addition of heparin ( 1 u/ml, porcine intestinal mucosal heparin, Sigma Co. USA ), marked enhancement of platelet aggregation was observed, compared with the degree of aggregation in the absence of heparin. However, in platelet suspensions prepared in modified Tyrode’s solution, heparin exhibited no potentiating effect on platelet aggregation induced by epinephrine or ADP. Potentiation of epinephrine- or ADP-induced platelet aggregation by heparin was demonstrated when purified AT was added to platelet suspensions at a concentration of 20 μg/ml. AT depleted plasma, which was prepared by immunosorption using matrix-bound antibodies to AT, retained no AT, while determination of α1-antitrypsinα2- macroglobulin and fibrinogen in AT depleted plasma produced values which corresponded to those of the original plasma when dilution factor was taken into account. The activities of coagulation factors were also comparable to those of the original plasma. Heparin exhibited potentiating effect on ADP- or epinephrine-induced aggregation of platelets in original plasma, but no effect in AT depleted plasma. When purified AT was added back to AT depleted plasma at a concentration of 20 μg/ml, potentiation of platelet aggregation by heparin was clearly demonstrated.Our results suggest that effect of heparin on platelet aggregation is also mediated by anti-thrombin III.

ІНТЕРПРЕТАЦІЯ КАТЕГОРІЇ РОЗВИТКУ В СУЧАСНІЙ ПСИХОЛОГІЇ

1970 ◽  
Vol 8 (1) ◽  
pp. 22-30
Author(s):  
Анжеліка Шамне
Keyword(s):  
Cultural Context ◽  
Developmental Psychology ◽  
Structure And Dynamics ◽  
Modern Psychology ◽  
Development Site ◽  
Approaches To Study ◽  
Methodological Approaches ◽  
Self Motion

У статті розглянуто сучасні підходи до інтерпретації категорії розвитку, розкрито теоретичні  та методологічні підходи до вивчення категорії розвитку у сучасній психології, визначено її психологічний  зміст,   моделі,   структуру   та   динаміку.   Категорія   розвитку   розглядається   як   епіцентр   наукової  проблематики у психології та як поняття інтегративного типу. Розвиток проаналізовано як категорію,  явище і проблему психології розвитку в різних аспектах аналізу. Розглянуто місце розвитку в системі  споріднених психологічних понять. У статті також аналізуються психологічні аспекти теоретичних та  методологічних  постнекласичних  тенденцій  вивчення  природи,  характеру  та  визначення  психічного  розвитку. Постнекласична парадигма та плюралістична методологія пізнання визначають розмитість  дисциплінарної мови  та  врахування  ролі  соціокультурного  контексту  при  вивченні  психологічних явищ.  Важливими тенденціями сучасного теоретико-методологічного стану психологічних досліджень розвитку  також є визнання неефективності моністичного підходу до його вивчення, взаємозв'язок теоретичних ідей  та   спроби   створення   метатеоретичних   схем,   постнекласичне   розуміння   розвитку   як   принципово  незавершеного   процесу   саморуху,   актуалізація   антропологічного   діапазону   проблем   та   посилення  спрямованості на роль культурного контексту в дослідженні розвитку людини.  The article deals with the modern approaches to the interpretation of the category of development, reveals  the theoretical and methodological approaches to study of development in modern psychology, its psychological  content, patterns, structure and dynamics. Category of development is viewed as an epicenter of scientific issues in  modern  psychology  and  the  concept  of  the  integrative  type.  Category  of  development  is  considered  as  the  phenomenon  and  the  problem  of  developmental  psychology  in  various  aspects  of  the  analysis.  Analyzed  the  development site in the related psychological concepts. The article analyzes the psychological aspects of theoretical  and methodological postnonclassical contemporary trends in the study of nature, character, and determination of  mental  development.  Postnonclassical  paradigm  and  pluralistic  methodology  of  knowledge  determine  the  disciplinary blurring and increase of the role of the analysis of socio-cultural context in the study of psychological  phenomenon. The important tendencies of modern theoretical and methodological state of psychological researches  of development are facts of inefficiency of the monistic approach to its study, interconnection of theoretical ideas  and   attempts   of  creating   metatheoretical   schemes,   postnonclassical   understanding   of   development   as   a  fundamentally  uncompleted  process  of  self-motion,  actualization  of  anthropological  range  of  problems  and  strengthening of focus on the role of cultural context in research of human development.   

Role of the family focused technologies in the clinical course of pregnancy at women of high obstetric risk

2016 ◽  
pp. 64-66
Author(s):  
S.Yu. Vdovichenko ◽  
Keyword(s):  
Comparison Group ◽  
Traditional Approach ◽  
Married Couple ◽  
Premature Births ◽  
Individual Support ◽  
The Family ◽  
Risk Patients ◽  
Individual Preparation

The objective: to show a role of the family focused technologies in depression of frequency of pathology of pregnancy at women of high obstetric risk. Patients and methods. For determination of efficiency of prophylaxis of pathology of pregnancy on the basis of use of the family focused technologies complex clinical-psychological and laboratory and tool examination of 300 women with factors of obstetric risk which were divided into two groups was conducted. In the main group – 182 women with motivation on partner labors to which provided training on system of individual preparation of married couple to labors. The comparison group consisted of 118 women who were not in prenatal training and had individual support in childbirth, with the traditional approach to pain management. Results. Use of the family focused technologies during pregnancy allows to reduce significantly the frequency of the main complications of pregnancy, especially not incubation and premature births. Conclusion. In our opinion, the technique is simple, available and can widely be used in practical health care at women with high obstetric risk. Key words: obstetric risk, the family focused technologies, prophylaxis.

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