scholarly journals Human cathepsin B1. Inhibition by α2-macroglobulin and other serum proteins

1973 ◽  
Vol 131 (4) ◽  
pp. 823-831 ◽  
Author(s):  
Phyllis M. Starkey ◽  
Alan J. Barrett
Keyword(s):  
Cathepsin B ◽  
Serum Proteins ◽  
Iodoacetic Acid ◽  
Active Enzyme ◽  
Molar Ratio ◽  
High Concentration ◽  
Α2 Macroglobulin ◽  
Normal Human ◽  
Human Cathepsin ◽  
Covalently Linked

1. Normal human serum was found to inhibit human cathepsin B1. 2. The major inhibitor present in serum was purified and identified as α2-macroglobulin. 3. α2-Macroglobulin was found to bind cathepsin B1 in an approximately 1:1 molar ratio. When bound, the enzyme retained about 50% of its proteolytic activity, and up to 80% of its activity against α-N-benzoyl-dl-arginine 2-naphthylamide. 4. Pretreatment of α2-macroglobulin with cathepsin B1 inactivated by exposure to pH8.5 or iodoacetic acid, in large molar excess, did not prevent the subsequent binding of active enzyme. Active enzyme, once bound, was not protected from inhibition by 1-chloro-4-phenyl-3-tosylamido-l-butan-2-one. 5. Cathepsin B1 was also inhibited by human immunoglobulin G, at high concentration. 6. Because it had been suggested that haptoglobin is responsible for the inhibition of ‘cathepsin B’ by serum, a method was devised for the selective removal of haptoglobin from mixtures of serum proteins by adsorption on haemoglobin covalently linked to Sepharose. No evidence was obtained that haptoglobin has any inhibitory activity against the enzyme.

scholarly journals Further characterization of the covalent linking reaction of α2-macroglobulin

1981 ◽  
Vol 195 (2) ◽  
pp. 453-461 ◽  
Author(s):  
G S Salvesen ◽  
C A Sayers ◽  
A J Barrett
Keyword(s):  
Steric Hindrance ◽  
Peptide Mapping ◽  
Thiol Group ◽  
Molar Ratio ◽  
Reactive Site ◽  
Reactive Group ◽  
Α2 Macroglobulin ◽  
Free Thiol Group ◽  
Covalently Linked

It is shown that non-proteolytic proteins can become covalently linked to alpha 2M (alpha 2-macroglobulin) during its reaction with proteinases, and that this probably occurs by the mechanism that leads to the covalent linking of proteinases described previously [Salvesen & Barrett (1980) Biochem. J. 187, 695-701]. The covalent linking of trypsin was at least partly dependent on the presence of unblocked lysine side chains on the protein. The covalent linking of proteinases was inhibited by nucleophiles of low Mr, and these compounds were themselves linked to alpha 2M in a molar ratio approaching one per quarter subunit. Peptide “mapping” indicated that the site of proteinase-mediated incorporation of the amines was the same as that at which methylamine is incorporated in the absence of a proteinase. The nucleophile-reactive site revealed in alpha 2M after reaction with a proteinase was shown to decay with a t1/2 of 112 s, at pH 7.5. After the reaction with a proteinase or with methylamine, a free thiol group was detectable on each subunit of alpha 2M. We propose that the site for incorporation of methylamine in each subunit is a thiol ester, which in S-alpha 2M (the electrophoretically “slow” form) is sterically shielded from reaction with large nucleophiles, but is revealed as a highly reactive group, free from steric hindrance, after the proteolytic cleavage. We have designated the activated species of the molecule “lpha 2M”.

scholarly journals The active-site residue Cys-29 is responsible for the neutral-pH inactivation and the refolding barrier of human cathepsin B

FEBS Letters ◽  
2000 ◽  
Vol 475 (3) ◽  
pp. 157-162 ◽  
Author(s):  
Jianxing Song ◽  
Ping Xu ◽  
Hui Xiang ◽  
Zhengding Su ◽  
Andrew C. Storer ◽  
...  
Keyword(s):  
Active Site ◽  
Cathepsin B ◽  
Active Site Residue ◽  
Neutral Ph ◽  
Ph Inactivation ◽  
Human Cathepsin

Study on the Inclusion Behavior of Cucurbit [n] uril with Phenylalanine

2011 ◽  
Vol 197-198 ◽  
pp. 1153-1156
Author(s):  
Ning Chen ◽  
Ya Bin Li
Keyword(s):  
1H Nmr ◽  
Interaction Mechanism ◽  
Acetate Buffer Solution ◽  
Molar Ratio ◽  
High Concentration ◽  
Buffer Solution ◽  
Visible Absorption ◽  
Nmr Spectrum ◽  
Application Range ◽  
Uv Visible

The characteristics of host-guest complexes between cucurbit[n]uril (CB [n]) and phenylalanine were investigated by UV-visible absorption spectroscopy in acetate buffer solution at room temperature. It was found that the UV-visible absorption increased steadily with constantly dropping the high concentration of cucurbit[6]uril (CB [6]) and cucurbit[8]uril (CB [8]) in the phenylalanine solution which indicates that there are some interaction betweenCB [n] and phenylalanine.Then CB [6] and phenylalanine at molar ratio of 1:1 to weigh while CB [8] and phenylalanine at molar ratio of 1:2, respectively, are both demonstrated by 1H NMR spectra. 1H NMR spectrum of complexes was obtained, indicating an enthalpic driving force for host-guest complexes. The possible interaction mechanism and inclusion mode were also discussed. This work may extend the application range of CB [n] in supramolecular and pharmaceutical analysis.

Serum Protein Concentrations in Normal Children

1971 ◽  
Vol 40 (1) ◽  
pp. 67-71 ◽  
Author(s):  
Berenice Abrams
Keyword(s):  
Young Adults ◽  
Serum Protein ◽  
Protein Level ◽  
Serum Proteins ◽  
Specific Component ◽  
Normal Children ◽  
Protein Levels ◽  
Group Specific Component ◽  
Α2 Macroglobulin ◽  
Age Range

1. Serum proteins were studied in 106 children ranging from 3 to 14 years using a modification of Laurell's method of quantitative immunoelectrophoresis. 2. Quantitative values are given for eleven proteins, viz.: α1 lipoprotein, α1 antitrypsin, α1 easily precipitable glycoprotein, α1 group specific component, α2 macroglobulin, caeruloplasmin, haptoglobin, transferrin, haemopexin, β lipoprotein, and β1AC(C3). 3. There were no significant differences in protein levels between the sexes, and no correlation between age and protein level within the age range studied. 4. The values were also compared with those of infants aged 6–12 months, young adults of 16–25 years, and adults of 16–65 years.

scholarly journals Purification of cathepsin B by a new form of affinity chromatography

1986 ◽  
Vol 235 (3) ◽  
pp. 731-734 ◽  
Author(s):  
D H Rich ◽  
M A Brown ◽  
A J Barrett
Keyword(s):  
Affinity Chromatography ◽  
Cathepsin B ◽  
Single Step ◽  
Starting Material ◽  
High Yield ◽  
Cysteine Proteinases ◽  
New Form ◽  
Human Cathepsin ◽  
Sepharose 4B

Human cathepsin B was purified by affinity chromatography on the semicarbazone of Gly-Phe-glycinal linked to Sepharose 4B, with elution by 2,2′-dipyridyl disulphide at pH 4.0. The product obtained in high yield by the single step from crude starting material was 80-100% active cathepsin B. The possibility that this new form of affinity chromatography may be of general usefulness in the purification of cysteine proteinases is discussed.

scholarly journals The two cathepsin B-like proteases of Arabidopsis thaliana are closely related enzymes with discrete endopeptidase and carboxydipeptidase activities

2018 ◽  
Vol 399 (10) ◽  
pp. 1223-1235 ◽  
Author(s):  
Andreas Porodko ◽  
Ana Cirnski ◽  
Drazen Petrov ◽  
Teresa Raab ◽  
Melanie Paireder ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Active Site ◽  
Cathepsin B ◽  
Cysteine Proteinase ◽  
Site Directed Mutagenesis ◽  
Single Amino Acid ◽  
Substrate Specificities ◽  
Active Site Cleft ◽  
Molecular Modeling Studies ◽  
Human Cathepsin

Abstract The genome of the model plant Arabidopsis thaliana encodes three paralogues of the papain-like cysteine proteinase cathepsin B (AtCathB1, AtCathB2 and AtCathB3), whose individual functions are still largely unknown. Here we show that a mutated splice site causes severe truncations of the AtCathB1 polypeptide, rendering it catalytically incompetent. By contrast, AtCathB2 and AtCathB3 are effective proteases which display comparable hydrolytic properties and share most of their substrate specificities. Site-directed mutagenesis experiments demonstrated that a single amino acid substitution (Gly336→Glu) is sufficient to confer AtCathB2 with the capacity to tolerate arginine in its specificity-determining S2 subsite, which is otherwise a hallmark of AtCathB3-mediated cleavages. A degradomics approach utilizing proteome-derived peptide libraries revealed that both enzymes are capable of acting as endopeptidases and exopeptidases, releasing dipeptides from the C-termini of substrates. Mutation of the carboxydipeptidase determinant His207 also affected the activity of AtCathB2 towards non-exopeptidase substrates, highlighting mechanistic differences between plant and human cathepsin B. This was also noted in molecular modeling studies which indicate that the occluding loop defining the dual enzymatic character of cathepsin B does not obstruct the active-site cleft of AtCathB2 to the same extent as in its mammalian orthologues.

scholarly journals Arsenic (III) Removal from a High-Concentration Arsenic (III) Solution by Forming Ferric Arsenite on Red Mud Surface

Minerals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 583
Author(s):  
Dongdong He ◽  
Yuming Xiong ◽  
Li Wang ◽  
Wei Sun ◽  
Runqing Liu ◽  
...  
Keyword(s):  
Red Mud ◽  
Arsenic Removal ◽  
Ferric Hydroxide ◽  
Morphological Properties ◽  
Molar Ratio ◽  
Inorganic Pollutants ◽  
High Concentration ◽  
Initial Concentration ◽  
X Ray ◽  
Alkaline Agent

Arsenic (As) is considered one of the most serious inorganic pollutants, and the wastewater produced in some smelters contains a high concentration of arsenic. In this paper, we purified the high-concentration arsenic solution with red mud and Fe3+ synergistically. In this system, arsenite anions reacted with Fe(III) ions to form ferric arsenite, which attached on the surface of red mud particles. The generated red mud/Fe1−x(As)x(OH)3 showed a better sedimentation performance than the pure ferric arsenite, which is beneficial to the separation of arsenic from the solution. The red mud not only served as the carrier, but also as the alkaline agent and adsorbent for arsenic treatment. The effects of red mud dosage, dosing order, pH, and molar ratio of Fe/As on arsenic removal were investigated. The efficiency of arsenic removal increased from a pH of 2 to 6 and reached equilibrium at a pH of 7. At the Fe/As molar ratio of 3, the removal efficiency of arsenic ions with an initial concentration of 500 mg/L reached 98%. In addition, the crystal structure, chemical composition, and morphological properties of red mud and arsenic removal residues (red mud/Fe1−x(As)x(OH)3) were characterized by XRD, XPS, X-ray fluorescence (XRF), SEM-EDS, and Raman spectroscopy to study the mechanism of arsenic removal. The results indicated that most of the arsenic was removed from the solution by forming Fe1−x(As)x(OH)3 precipitates on the red mud surface, while the remaining arsenic was adsorbed by the red mud and ferric hydroxide.

scholarly journals Effect of LiNO3 on Expansion of Alkali–Silica Reaction in Rock Prisms and Concrete Microbars Prepared by Sandstone

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1150 ◽  
Author(s):  
Jinxin Liu ◽  
Lanqing Yu ◽  
Min Deng
Keyword(s):  
Electron Microscope ◽  
Critical Concentration ◽  
Stress Test ◽  
Molar Ratio ◽  
Alkali Silica Reaction ◽  
X Ray Diffraction ◽  
High Concentration ◽  
X Ray ◽  
Long Period ◽  
Scanning Electron

The aim of this research is to investigate the effect of LiNO3 on the alkali–silica reaction (ASR) expansion of reactive sandstone and the mechanism through which this occurs. This paper presents the results from tests carried out on rock prisms and concrete microbars prepared by sandstone and LiNO3. The findings show that LiNO3 does not decrease the expansion of these samples unless the molar ratio of [Li]/[Na + K] exceeds 1.66, and the expansion is greatly increased when its concentration is below this critical concentration. The expansion stress test proves that Li2SiO3 is obviously expansive. X-ray diffraction (XRD) and scanning electron microscope (SEM) results indicate that LiNO3 reacts with the microcrystalline quartz inside sandstone, inhibiting the formation of ASR gel, and the formation of Li2SiO3 causes larger expansion. A high concentration of LiNO3 might inhibit the ASR reaction in the early stages, and the formation of Li2SiO3 causes expansion and cracks in concrete after a long period of time.

Optimizing Nephelometric Measurement of Specific Serum Proteins: Evaluation of Three Diluents

1974 ◽  
Vol 20 (12) ◽  
pp. 1548-1552 ◽  
Author(s):  
Lawrence M Killingsworth ◽  
Gregory J Buffone ◽  
Meena B Sonawane ◽  
Glennie C Lunsford
Keyword(s):  
Steady State ◽  
Continuous Flow ◽  
Reaction Rate ◽  
Serum Proteins ◽  
Physiological Saline ◽  
Rate Analysis ◽  
Specific Serum ◽  
State Approximation ◽  
Α2 Macroglobulin ◽  
Steady State Approximation

Abstract Three diluents were studied, to determine which is the best for the automated immunochemical measurement of specific serum proteins. Nine serum proteins (orosomucoid, α1-antitrypsin, α2-macroglobulin, haptoglobin, transferrin, C3, IgG, IgA, and IgM) were measured in physiological saline (9 g NaCI/liter), tris(hydroxymethyl)aminomethane buffer (0.01 mol/liter; pH 7.4), and physiological saline containing polyethylene glycol ("PEG 6000," 40 g/liter). Criteria were: reaction rate, analysis rate, carryover between samples, steady-state approximation, precision, and correlation with other methods. Saline containing polyethylene giycol is the best of the three diluents for use in continuous-flow nephelometric analysis of serum proteins.

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