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1.
Eight different di- and tripeptidyl aldehyde derivatives, each having at its C-terminus an aldehyde analog of L-norleucine, L-methionine, or L-phenylalanine with a preceding L-leucine residue, were synthesized and tested for their inhibitory effects on several serine and cysteine endopeptidases. These compounds showed almost no inhibition of trypsin, and only weak inhibition of alpha-chymotrypsin and cathepsin H, while they exhibited marked inhibition of cathepsin B less than calpain II congruent to calpain I less than cathepsin L, being stronger in this order. The mode of inhibition of these cysteine proteinases was competitive for the peptide substrate used and inhibitor constants (Ki) were calculated from the Dixon plot. The best inhibitors found were: 4-phenyl-butyryl-Leu-Met-H for calpain I (Ki, 36 nM) and calpain II (Ki, 50 nM); acetyl-Leu-Leu-nLeu-H for cathepsin L (Ki, 0.5 nM); acetyl-Leu-Leu-Met-H for cathepsin B (Ki, 100 nM).  相似文献   

2.
A low-Mr tight binding proteinase inhibitor was purified from bovine muscle by alkaline denaturation of cysteine proteinases, gel filtration on Sexphadex G-75 and affinity chromatography on carboxymethyl-papain-Sepharose. Chromatofocusing separated three isoforms which are similar in their Mr of about 14 000, their stability with heating at 80°C and their inhibitory activity towards cathepsin H, cathepsin B and papain. The equilibrium constants (Ki) were determined for these three cysteine proteinases but for cathepsin H, association (kass) and dissociation (kdiss) rate constants were also evaluated. Ki values of 56 nM and 8.4 nM were found for cathepsin B and cathepsin H, respectively. For papain, Ki was in the range of 0.1–1 nM. The kinetic features of enzyme-inhibitor binding suggest a possible role for this low-Mr protein inhibitor in controlling ‘in vivo’ cathepsin H proteolytic activity. With regard to cathepsin B, such a physiological role was less evident.  相似文献   

3.
Cathepsins B and L belong to the papain superfamily of cysteine proteases and play important roles in various physiological and pathological processes. In the course of studies on their inhibitors, we examined the inhibitory effects of the peptide aldehyde benzyloxycarbonyl-leucyl-leucyl-leucinal (ZLLLal) and its analogues. As a result, rat liver cathepsins B and L were shown to be strongly inhibited by them. The concentration required for 50% inhibition (IC50) by ZLLLal was 88 nM for cathepsin B and 163 nM for cathepsin L. Moreover, various analogues of ZLLLal, including 2-furancarbonyl-, nicotinyl-, isonicotinyl- and 4-morpholinylsuccinyl-LLLals, and some acetyl-Pro (AcP)-containing analogues, AcPLLLal and AcPPLLLal, were shown to inhibit both enzymes more strongly than ZLLLal. Among them, isonicotinyl-LLLal was most inhibitory against both cathepsins B (IC50, 12 nM) and L (IC50, 20 nM). Several of these inhibitors were indicated to be somewhat more soluble in aqueous media than ZLLLal.  相似文献   

4.
A library of cathepsin S inhibitors of the dipeptide nitrile chemotype, bearing a bioisosteric sulfonamide moiety, was synthesized. Kinetic investigations were performed at four human cysteine proteases, i.e. cathepsins S, B, K and L. Compound 12 with a terminal 3-biphenyl sulfonamide substituent was the most potent (Ki = 4.02 nM; selectivity ratio cathepsin S/K = 5.8; S/L = 67) and 24 with a 4′-fluoro-4-biphenyl sulfonamide substituent the most selective cathepsin S inhibitor (Ki = 35.5 nM; selectivity ratio cathepsin S/K = 57; S/L = 31). In silico design and biochemical evaluation emphasized the impact of the sulfonamide linkage on selectivity and a possible switch of P2 and P3 substituents with respect to the occupation of the corresponding binding sites of cathepsin S.  相似文献   

5.
A series of peptidyldiazomethanes was synthesized and tested as inactivators of the cysteine proteinases calpain II, cathepsin L and cathepsin B. Inactivators that react rapidly and that show a degree of selectivity between the enzymes were identified. Z-Tyr(I)-Ala-CHN2 (where Z represents benzyloxycarbonyl) reacts rapidly with cathepsin L and more slowly with cathepsin B, but does not inhibit calpain II. Z-Leu-Leu-Tyr-CHN2 reacts rapidly with cathepsin L and calpain II but very slowly with cathepsin B. Boc-Val-Lys(epsilon-Z)Leu-Tyr-CHN2 (where Boc represents t-butyloxycarbonyl) reacts more rapidly with calpain II than with cathepsin L or cathepsin B. The discriminating inhibitory effects of these compounds make them potentially useful for investigation of enzyme functions in vivo. The data presented also provide insights into the subsite specificity of calpain.  相似文献   

6.
Human carbonic anhydrase I and II isoenzymes (hCA I and II) and acetylcholinesterase (AChE) are important metabolic enzymes that are closely associated with various physiological and pathological processes. In this study, we investigated the inhibition effects of some sulfonamides on hCA I, hCA II, and AChE enzymes. Both hCA isoenzymes were purified by Sepharose‐4B‐L‐Tyrosine‐5‐amino‐2‐methylbenzenesulfonamide affinity column chromatography with 1393.44 and 1223.09‐folds, respectively. Also, some inhibition parameters including IC50 and Ki values were determined. Sulfonamide compounds showed IC 50 values of in the range of 55.14 to 562.62 nM against hCA I, 55.99 to 261.96 nM against hCA II, and 98.65 to 283.31 nM against AChE. Ki values were in the range of 23.40 ± 9.10 to 365.35 ± 24.42 nM against hCA I, 45.87 ± 5.04 to 230.08 ± 92.23 nM against hCA II, and 16.00 ± 45.53 to 157.00 ± 4.02 nM against AChE. As a result, sulfonamides had potent inhibition effects on these enzymes. Therefore, we believe that these results may contribute to the development of new drugs particularly in the treatment of some disorders.  相似文献   

7.
The carbonic anhydrases (CAs, EC 4.2.1.1) represent a superfamily of widespread enzymes, which catalyze a crucial biochemical reaction, the reversible hydration of carbon dioxide to bicarbonate and protons. Human CA isoenzymes I and II (hCA I and hCA II) are ubiquitous cytosolic isoforms. In this study, a series of hydroperoxides, alcohols, and acetates were tested for the inhibition of the cytosolic hCA I and II isoenzymes. These compounds inhibited both hCA isozymes in the low nanomolar ranges. These compounds were good hCA I inhibitors (Kis in the range of 24.93–97.99?nM) and hCA II inhibitors (Kis in the range of 26.04–68.56?nM) compared to acetazolamide as CA inhibitor (Ki: 34.50?nM for hCA I and Ki: 28.93?nM for hCA II).  相似文献   

8.
Excessive calpain activations contribute to serious cellular damage and have been found in many pathological conditions. Novel chromone carboxamides derived from ketoamides were prepared and evaluated for mu-calpain inhibition. Among synthesized, compound 2i was the most potent calpain inhibitor with an IC(50) value of 0.24 +/- 0.11 microM comparable to the activity of peptide aldehyde calpain inhibitor MDL 28,170. Furthermore, compound 2i showed higher selectivity for mu-calpain over two related cysteine proteases cathepsin B and cathepsin L, suggesting the chromone ring as a good scaffold for selective mu-calpain inhibitors.  相似文献   

9.
A small library of 36 functionalized benzophenone thiosemicarbazone analogs has been prepared by chemical synthesis and evaluated for their ability to inhibit the cysteine proteases cathepsin L and cathepsin B. Inhibitors of cathepsins L and B have the potential to limit or arrest cancer metastasis. The six most active inhibitors of cathepsin L (IC50 < 85 nM) in this series incorporate a meta-bromo substituent in one aryl ring along with a variety of functional groups in the second aryl ring. These six analogs are selective for their inhibition of cathepsin L versus cathepsin B (IC50 > 10,000 nM). The most active analog in the series, 3-bromophenyl-2′-fluorophenyl thiosemicarbazone 1, also efficiently inhibits cell invasion of the DU-145 human prostate cancer cell line.  相似文献   

10.
A series of 24 novel heterocyclic compounds—functionalized at position 4 with aldehyde (5a5f), carboxylic acid (6a6f), nitrile (7a7f) and oxime (8a8f) functional groups—bearing 6-aminosulfonybenzothiazole moiety at position 1 of pyrazole has been synthesized and investigated for the inhibition of four isoforms of the α-class carbonic anhydrases (CAs, EC 4.2.1.1), comprising hCAs I and II (cytosolic, ubiquitous isozymes) and hCAs IX and XII (transmembrane, tumor associated isozymes). Against the human isozyme hCA I, compounds 6a6f showed medium-weak inhibitory potential with Ki values in the range of 157–690 nM with 6a showing better potential than the standard drug acetazolamide (AZA). Against hCA II, all the compounds showed excellent to moderate inhibition with Ki values of compounds 5a, 5d, 5f, 6a6f, 8d and 8f lower than 12 nM (Ki of AZA). Against hCA IX, all the compounds showed moderate inhibition with the exception of 6e which showed nearly 9 fold a better profile compared to AZA, whereas against hCA XII, four compounds 6e, 7a, 7b and 7d showed Ki in the same order as that of AZA. Carboxylic acid 6e was found to be an excellent inhibitor of both hCA IX and XII, with Ki values of 2.8 nM and 5.5 nM, respectively.  相似文献   

11.
A series of carbamate derivatives were synthesized and their carbonic anhydrase I and II isoenzymes and acetylcholinesterase enzyme (AChE) inhibitory effects were investigated. All carbamates were synthesized from the corresponding carboxylic acids via the Curtius reactions of the acids with diphenyl phosphoryl azide followed by addition of benzyl alcohol. The carbamates were determined to be very good inhibitors against for AChE and hCA I, and II isoenzymes. AChE inhibition was determined in the range 0.209–0.291?nM. On the other hand, tacrine, which is used in the treatment of Alzheimer’s disease possessed lower inhibition effect (Ki: 0.398?nM). Also, hCA I and II isoenzymes were effectively inhibited by the carbamates, with inhibition constants (Ki) in the range of 4.49–5.61?nM for hCA I, and 4.94–7.66?nM for hCA II, respectively. Acetazolamide, which was clinically used carbonic anhydrase (CA) inhibitor demonstrated Ki values of 281.33?nM for hCA I and 9.07?nM for hCA II. The results clearly showed that AChE and both CA isoenzymes were effectively inhibited by carbamates at the low nanomolar levels.  相似文献   

12.
A series of vinyl functionalized 5,6-dimethylbenzimidazolium salts are synthesized. All compounds were fully characterized by elemental analyses, MS, 1H-NMR, 13C-NMR, and IR spectroscopy techniques. Enzyme inhibition is a very active area of research in drug design and development. In this study, the synthesized novel benzimidazolium salts were evaluated toward the human erythrocyte carbonic anhydrase I (hCA I), and II (hCA II) isoenzymes, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes. They demonstrated highly potent inhibition ability against hCA I with Ki values of 484.8 ± 62.6–1389.7 ± 243.2 nM, hCA II with Ki values of 298.9 ± 55.7–926.1 ± 330.0 nM, α-glycosidase with Ki values of 170.3 ± 27–760.1 ± 269 μM, AChE with Ki values of 27.1 ± 3–77.6 ± 1.7 nM, and BChE with Ki values of 21.0 ± 5–61.3 ± 15 nM. As a result, novel vinyl functionalized 5,6-dimethylbenzimidazolium salts (1a–g) exhibited effective inhibition profiles toward studied metabolic enzymes. Therefore, we believe that these results may contribute to the development of new drugs particularly to treat some global disorders including glaucoma, Alzheimer's disease, and diabetes.  相似文献   

13.
Cathepsin L of cancer cells has been shown to play an important role in degradation of extracellular matrix for metastasis. In order to reduce cell invasion, cathepsin L propeptide-like proteins which are classified as the I29 family in the MEROPS peptidase database were characterized from Calotropis procera R. Br., rich in cysteine protease. Of 19 candidates, the cloned and expressed recombinant SnuCalCp03-propeptide (rSnuCalCp03-propeptide) showed a low nanomolar Ki value of 2.3?±?0.2?nM against cathepsin L. A significant inhibition of tumor cell invasion was observed with H1975, HT29, MDA-BM-231, PANC1, and PC3 with a 76, 67, 67, 63, and 79% reduction, respectively, in invasion observed in the presence of 400?nM of the rSnuCalCp03-propeptide. In addition, thermal and pH study showed rSnuCalCp03-propeptide consisting of secondary structures was stable at a broad range of temperatures (30–70?°C) and pH (2–10, except for 5 which is close to the isoelectric point of 5.2).  相似文献   

14.
Selective proteinase inhibitors have demonstrated utility in the investigation of cartilage degeneration mechanisms and may have clinical use in the management of osteoarthritis. The cysteine protease cathepsin K (CatK) is an attractive target for arthritis therapy. Here we report the synthesis of two cathepsin K inhibitors (CKIs): racemic azanitrile derivatives CKI-E and CKI-F, which have better inhibition properties on CatK than the commercial inhibitor odanacatib (ODN). Their IC50 values and inhibition constants (Ki) have been determined in vitro. Inhibitors demonstrate differential selectivity for CatK over cathepsin B, L and S in vitro, with Ki amounting to 1.14 and 7.21?nM respectively. We analyzed the effect of these racemic inhibitors on viability in different cell types. The human osteoblast-like cell line MG63, MOVAS cells (a murine vascular smooth muscle cell line) or murine primary chondrocytes, were treated either with CKI-E or with CKI-F, which were not toxic at doses of up to 5?µM. Primary chondrocytes subjected to several passages were used as a model of phenotypic loss of articular chondrocytes, occurring in osteoarthritic cartilage. The efficiency of CKIs regarding CatK inhibition and their specificity over other proteases were validated in primary chondrocytes subjected to several passages. Racemic CKI-E and CKI-F at 0.1 and 1?µM significantly inhibited CatK activity in dedifferentiated chondrocytes, even better than the commercial CatK inhibitor ODN. The enzymatic activity of other proteases such as matrix metalloproteinases or aggrecanases were not affected. Taken together, these findings support the possibility to design CatK inhibitors for preventing cartilage degradation in different pathologies.  相似文献   

15.
The novel N‐propylphthalimide‐substituted and 4‐vinylbenzyl‐substituted N‐heterocyclic carbene (NHC) precursors were synthesized by N‐substituted benzimidazolium with aryl halides. The novel N‐propylphthalimide‐substituted and 4‐vinylbenzyl‐substituted NHC precursors have been characterized by using 1H NMR, 13C NMR, FTIR spectroscopy, and elemental analysis techniques. They were tested for the inhibition of AChE and hCA enzymes and demonstrated efficient inhibition profiles with Ki values in the range of 351.0–1269.9 nM against hCA I, 346.6–1193.1 nM against hCA II, and 19.0–76.3 nM against AChE. On the other hand, acetazolamide, a clinically used molecule, utilized as CA inhibitor, obtained a Ki value of 1246.7 nM against hCA I and 1407.6 nM against hCA II. Additionally, tacrine inhibited AChE and obtained a Ki value of 174.6 nM.  相似文献   

16.
Cathespin L (EC 3.4.22.15) and cathepsin H (EC 3.4.22.16) have been purified from brain cortex to apparent homogeneity by a simultaneous procedure involving acid extraction of homogenate at pH 4.2, ammonium sulfate fractionation (30–80%), chromatography on pepstatin-Sepharose, CM-Sephadex C-50, DEAE-Sephadex A-50, phenyl- and concanavalin A-Sepharose and isoelectric focusing. Cathepsin L and cathepsin H were assayed in the presence of dithiothreitol and Na2EDTA (2 mM each) with Z-Phe-Arg-NHMec (pH 5.5) and Lys-NNa (pH 6.5) respectively. Cathepsin L consists of 2 polypeptide chains with Mr 25 000 and 5 000, Mr of cathepsin H is 28 000. Cathepsin L exists in brain tissue in two multiple forms with pI values 5.7 and 5.9, pI of cathepsin H is 6.8. Substrate specificity of these thiol proteinases was tested with proteins (pyridoxyl-hemoglobin, azocasein) and low Mr naphthylamide and methylcoumarylamide substrates: Lys-NNa, Arg-NNa, Dz-Arg-NNa, Z-Arg-Arg-NNaOMe, Z-Phe-Arg-NHMec, Z-Phe, Val-Arg-NHMec, Z-Gly-Gly-Arg-NHMec. Z-Phe-Arg-NHMec is the best substrate for cathepsin L (KM=5 M, Kcat=21 s–1), Arg-NNa—for cathepsin H (KM=0.1 mM, Kcat=1.93 s–1), being endoaminopeptidase cathepsin H also hydrolyses Bz-Arg-NNa (KM=0.7 mM, Kcat=1.3 s–1). Both proteinases are inhibited by traditional inhibitors of cysteine proteinases and E-64, but leupeptin turned to be more effective inhibitor of cathepsin L (Ki=2.4 nM) than of cathepsin H (Ki=9.2 M), the latter enzyme being sensitive to puromycin and benzethonium chloride as well. Z-Phe-Phe-CHN2 and Z-Phe-Ala-CHN2 are potent irreversible inhibitors of brain cathepsin L with K2nd 150 000 and 137 000 M–1 s–1 respectively. Properties of the enzymes from human and bovine brain are similar.Special Issue Dedicated to Dr. Abel Lajtha.  相似文献   

17.
The prodomains of several cysteine proteases of the papain family have been shown to be potent inhibitors of their parent enzymes. An increased interest in cysteine proteases inhibitors has been generated with potential therapeutic targets such as cathepsin K for osteoporosis and cathepsin S for immune modulation. The propeptides of cathepsin S, L and K were expressed as glutathione S-transferase-fusion proteins in Escherichia coli. The proteins were purified on glutathione affinity columns and the glutathione S-transferase was removed by thrombin cleavage. All three propeptides were tested for inhibitor potency and found to be selective within the cathepsin L subfamily (cathepsins K, L and S) compared with cathepsin B or papain. Inhibition of cathepsin K by either procathepsin K, L or S was time-dependent and occurred by an apparent one-step mechanism. The cathepsin K propeptide had a Ki of 3.6-6.3 nM for each of the three cathepsins K, L and S. The cathepsin L propeptide was at least a 240-fold selective inhibitor of cathepsin K (Ki = 0.27 nM) and cathepsin L (Ki = 0.12 nM) compared with cathepsin S (Ki = 65 nM). Interestingly, the cathepsin S propeptide was more selective for inhibition of cathepsin L (Ki = 0.46 nM) than cathepsin S (Ki = 7.6 nM) itself or cathepsin K (Ki = 7.0 nM). This is in sharp contrast to previously published data demonstrating that the cathepsin S propeptide is equipotent for inhibition of human cathepsin S and rat and paramecium cathepsin L [Maubach, G., Schilling, K., Rommerskirch, W., Wenz, I., Schultz, J. E., Weber, E. & Wiederanders, B. (1997), Eur J. Biochem. 250, 745-750]. These results demonstrate that limited selectivity of inhibition can be measured for the procathepsins K, L and S vs. the parent enzymes, but selective inhibition vs. cathepsin B and papain was obtained.  相似文献   

18.
In order to identify potential calpain and cathepsin inhibitors we prepared 12 dihydroxychalcone analogues and tested their ability to inhibit μ-calpain, m-calpain, cathepsins B and L. In the calpain inhibition test, compound 10 exhibited the most active inhibitory activity against m-calpain with an IC50 value of 25.25 ± 0.901 μM. With respect to inhibition of cathepsins B and L, compound 13 exhibited the most potent inhibitory activity on cathepsin L and moderate inhibitory activity on cathepsin B with IC50 values of 2.80 ± 0.100 and 11.47 ± 0.087 μM, respectively. Our results suggest the possibility of developing dual calpain and cathepsin inhibitors by properly modulating structures and/or combining the essential aspects of the functional group effective for specific calpain and cathepsin inhibition.  相似文献   

19.
In this work, the inhibitory activity of Voriconazole was measured against some metabolic enzymes, including human carbonic anhydrase (hCA) I and II isoenzymes, acetylcholinesterase (AChE), and α‐glycosidase; the results were compared with standard compounds including acetazolamide, tacrine, and acarbose. Half maximal inhibition concentration (IC50) values were obtained from the enzyme activity (%)‐[Voriconazole] graphs, whereas Ki values were calculated from the Lineweaver‐Burk graphs. According to the results, the IC50 value of Voriconazole was 40.77 nM for α‐glycosidase, while the mean inhibition constant (Ki) value was 17.47 ± 1.51 nM for α‐glycosidase. The results make an important contribution to drug design and have pharmacological applications. In addition, the Voriconazole compound demonstrated excellent inhibitory effects against AChE and hCA isoforms I and II. Voriconazole had Ki values of 29.13 ± 3.57 nM against hCA I, 15.92 ± 1.90 nM against hCA II, and 10.50 ± 2.46 nM against AChE.  相似文献   

20.
Compounds containing nitrogen and sulfur atoms can be widely used in various fields, including industry, medicine, biotechnology, and chemical technology. Among them, amides of acids and heterocyclic compounds have an important place. These amides and thiazolidine‐4‐ones showed good inhibitory action against butyrylcholinesterase (BChE), acetylcholinesterase (AChE), and human carbonic anhydrase isoforms. AChE exists at high concentrations in the brain and red blood cells. BChE is an important enzyme that is plentiful in the liver, and it is released into the blood in a soluble form. They were demonstrated to have effective inhibition profiles with Ki values of 23.76–102.75 nM against hCA I, 58.92–136.64 nM against hCA II, 1.40–12.86 nM against AChE, and 9.82–52.77 nM against BChE. On the other hand, acetazolamide showed Ki value of 482.63 ± 56.20 nM against hCA I, and 1019.60 ± 163.70 nM against hCA II. Additionally, Tacrine inhibited AChE and BChE, showing Ki values of 397.03 ± 31.66 and 210.21 ± 15.98 nM, respectively.  相似文献   

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