共查询到20条相似文献,搜索用时 484 毫秒
1.
Purification and properties of the hexosaminidase A-activating protein from human liver 总被引:3,自引:0,他引:3
下载免费PDF全文
![点击此处可从《The Biochemical journal》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Human liver extracts contain an activating protein which is required for hexosaminidase A-catalysed hydrolysis of the N-acetylgalactosaminyl linkage of GM2 ganglioside [N-acetylgalactosaminyl-(N-acetylneuraminyl) galactosylglucosylceramide]. A partially purified preparation of human liver hexosaminidase A that is substantially free of GM2 ganglioside hydrolase activity is used to assay the activating protein. The proceudres of heat and alcohol denaturation, ion-exchange chromatography and gel filtration were used to purify the activating protein over 100-fold from crude human liver extracts. When the purified activating protein is analysed by polyacrylamide-gel disc electrophoresis, two closely migrating protein bands are seen. When purified activating protein is used to reconstitute the GM2 ganglioside hydrolase activity, the rate of reaction is proportional to the amount of hexosaminidase A used. The activation is specific for GM2 ganglioside and and hexosaminidase A. The activating protein did not stimulate hydrolysis of asialo-GM2 ganglioside by either hexosaminidase A or B. Hexosaminidase B did not catalyse hydrolysis of GM2 ganglioside with or without the activator. Kinetic experiments suggest the presence of an enzyme–activator complex. The dissociation constant of this complex is decreased when higher concentrations of substrate are used, suggesting the formation of a ternary complex between enzyme, activator and substrate. Determination of the molecular weight of the activating protein by gel-filtration and sedimentation-velocity methods gave values of 36000 and 39000 respectively. 相似文献
2.
Summary Cultured skin fibroblasts from controls and patients with lysosomal storage diseases were loaded with GM1 ganglioside that had been labelled with tritium in its ceramide moiety. After a 65-h or 240-h incubation, a large percentage of this ganglioside remained undegraded in GM1 gangliosidoses, whereas in the other storage diseases studied, one of its metabolites accumulated by 2–4 fold relative to controls. Labelled GM2 ganglioside accumulated in 4 variants of GM2 gangliosidosis, whereas labelled GM3 ganglioside accumulated in sialidosis, galactosialidoses and sphingolipid activator protein 1 (SAP-1, saposin B) and prosaposin (saposin A, B, C an D) deficient lipidoses. The reduced degradation of GM3 ganglioside in the SAP-1 and prosaposin deficiencies was attributed to the deficient function of SAP-1. The prosaposin deficient cells also showed a reduced re-utilization of radioactive metabolites from GM1 ganglioside (i.e. sphingosine and fatty acid) for phospholipid biosynthesis compared with fibroblasts from the SAP-1 deficient patient or normal controls. This anomaly was ascribed to the previously shown defect in ceramide degradation in prosaposin deficiency. 相似文献
3.
Interaction of activating protein and surfactants with human liver hexosaminidase A and GM2 ganglioside 总被引:1,自引:1,他引:0
The effects of surfactants on the human liver hexosaminidase A-catalysed hydrolysis of Gm2 ganglioside were assessed. Some non-ionic surfactants, including Triton X-100 and Cutscum, and some anionic surfactants, including sodium taurocholate, sodium dodecyl sulphate, phosphatidylinositol and N-dodecylsarcosinate, were able to replace the hexosaminidase A-activator protein [Hechtman (1977) Can. J. Biochem. 55, 315–324; Hechtman & Leblanc (1977) Biochem. J. 167, 693–701) and also stimulated the enzymic hydrolysis of substrate in the presence of saturating concentrations of activator. Other non-ionic surfactants, such as Tween 80, Brij 35 and Nonidet P40, and anionic surfactants, such as phosphatidylethanolamine, did not enhance enzymic hydrolysis of Gm2 ganglioside and inhibited hydrolysis in the presence of activator. The concentration of surfactants at which micelles form was determined by measurements of the minimum surface-tension values of reaction mixtures containing a series of concentrations of surfactant. In the case of Triton X-100, Cutscum, sodium taurocholate, N-dodecylsarcosinate and other surfactants the concentration range at which stimulation of enzymic activity occurs correlates well with the critical micellar concentration. None of the surfactants tested affected the rate of hexosaminidase A-catalysed hydrolysis of 4-methylumbelliferyl N-acetyl-β-d-glucopyranoside. Both activator and surfactants that stimulate hydrolysis of Gm2 ganglioside decrease the Km for Gm2 ganglioside. Inhibitory surfactants are competitive with the activator protein. Evidence for a direct interaction between surfactants and Gm2 ganglioside was obtained by comparing gel-filtration profiles of 3H-labelled GM2 ganglioside in the presence and absence of surfactants. The results are discussed in terms of a model wherein a mixed micelle of surfactant or activator and GM2 ganglioside is the preferred substrate for enzymic hydrolysis. 相似文献
4.
Volkan Seyrantepe Pablo Lema Aurore Caqueret Larbi Dridi Samar Bel Hadj Stephane Carpentier Francine Boucher Thierry Levade Lionel Carmant Roy A. Gravel Edith Hamel Pascal Vachon Graziella Di Cristo Jacques L. Michaud Carlos R. Morales Alexey V. Pshezhetsky 《PLoS genetics》2010,6(9)
Tay-Sachs disease is a severe lysosomal disorder caused by mutations in the HexA gene coding for the α-subunit of lysosomal β-hexosaminidase A, which converts GM2 to GM3 ganglioside. Hexa−/− mice, depleted of β-hexosaminidase A, remain asymptomatic to 1 year of age, because they catabolise GM2 ganglioside via a lysosomal sialidase into glycolipid GA2, which is further processed by β-hexosaminidase B to lactosyl-ceramide, thereby bypassing the β-hexosaminidase A defect. Since this bypass is not effective in humans, infantile Tay-Sachs disease is fatal in the first years of life. Previously, we identified a novel ganglioside metabolizing sialidase, Neu4, abundantly expressed in mouse brain neurons. Now we demonstrate that mice with targeted disruption of both Neu4 and Hexa genes (Neu4
−/−;Hexa
−/−) show epileptic seizures with 40% penetrance correlating with polyspike discharges on the cortical electrodes of the electroencephalogram. Single knockout Hexa
−/− or Neu4
−/− siblings do not show such symptoms. Further, double-knockout but not single-knockout mice have multiple degenerating neurons in the cortex and hippocampus and multiple layers of cortical neurons accumulating GM2 ganglioside. Together, our data suggest that the Neu4 block exacerbates the disease in Hexa−/− mice, indicating that Neu4 is a modifier gene in the mouse model of Tay-Sachs disease, reducing the disease severity through the metabolic bypass. However, while disease severity in the double mutant is increased, it is not profound suggesting that Neu4 is not the only sialidase contributing to the metabolic bypass in Hexa
−/− mice. 相似文献
5.
A radioassay for the rapid determination of GM1, ganglioside concentration in small volumes of CSF from individual patients is described. The assay utilizes the high-affinity interaction between cholera enterotoxin and GM1 ganglioside. The lower detection limit of GM1 ganglioside by this radioassay under the described incubation conditions is 2.5 ng/ml. The radioassay-determined lumbar CSF GM1 ganglioside concentrations in a small group of patients with diverse neurologic disorders are presented. The radioassay GM1 ganglioside concentration is in good agreement with the GM1 ganglioside concentration determined, in one patient, by the tlc-densitometry technique. 相似文献
6.
The enzymatic basis for the differences in hepatic ganglioside patterns in the mouse strains C57Bl/6 and Swiss White (SW) was investigated. SW has a “Swiss-type” ganglioside profile, expressing GM1 ? and GD1a ? in addition to GM2 ? as major hepatic gangliosides, whereas C57Bl/6 shows a “GM2-type” profile, expressing only GM2 ? as the major hepatic ganglioside. The enzyme UDP-galactose:GM2 ganglioside galactosyltransferase (GM2-GalT), which catalyzes the synthesis of GM1 ganglioside, showed a four- to fivefold elevation in intact and solubilized liver Golgi membrane fractions of the SW strain compared to C57Bl/6. Crosses between C57Bl/6 and SW produced an F1 generation with a hepatic ganglioside and enzymatic phenotype intermediate between those of the two parental strains. All three genotypic groups show two forms of the Golgi apparatus enzyme with isoelectric points of 6.5–6.8 and 8.3–9.0. The simplest mode of action of genes which control the enzymatic phenotype that would be consistent with these findings are one or two structural genes or one or two cis-regulatory genes affecting the rate of enzyme synthesis. 相似文献
7.
Gangliosides were isolated from human brain myelin, oligodendroglia, and neurons. Quantitative analysis revealed the following ganglioside contents: myelin, 2.0; neurons, 1.3; and oligodendroglia, 0.35 μg ganglioside sialic acid per mg protein. Myclin had a relatively simple ganglioside pattern with GM4 and GM1 as the predominant ganglioside species. The ganglioside pattern of oligodendroglia was quite complex and it resembled that of whole white matter rather than that of myelin. A high concentration of GM4 was found in oligodendroglial fractions in addition to GM1, GD1a, GD1b, and GT1b. The usually- minor brain gangliosides GM3, GM2, and GM3 were also enriched in oligodendroglia. The neuronal ganglioside pattern was generally similar to the pattern of whole gray matter. Both neurons and whole gray matter contained very low amounts of GM4. These results indicate that GM4 is specifically localized in myelin and oligodendroglia of the CNS. Evidence is also presented that myelin, but not oligodendroglia, is the major reservoir of human white matter GM1 and GM4. 相似文献
8.
Bruno Venerando Benvenuto Cestaro Amelia Fiorilli Riccardo Ghidoni Augusto Preti Guido Tettamanti 《The Biochemical journal》1982,203(3):735-742
Gd1a, Gd1b and Gt1b gangliosides were dispersed in the following membrane-mimicking systems: (a) homogeneous micelles; (b) mixed micelles with Gm1 ganglioside (which is resistant to the enzyme action), Triton X-100 or bovine serum albumin; (c) small unilamellar vesicles of egg phosphatidylcholine. The effect of dispersion on sialic acid release by Vibrio cholerae sialidase was studied. As reference substrates freely interacting with the enzyme the lipid-free carbohydrates of Gd1a and 3′-sialosyl-lactose were employed. The apparent Vmax. of the enzyme was, with all the gangliosides, dependent on the type of ganglioside dispersion. It was lowest for homogeneous micelles and mixed micelles with ganglioside Gm1, and increased about 6-fold for ganglioside/bovine serum albumin lipoprotein micelles, 15-fold for mixed-ganglioside/Triton X-100 micelles (optimal molar ratio 1:7.5) and 30-fold for phosphatidylcholine vesicles containing 2.5 mol% ganglioside (this proportion was optimal for enzyme activity on the vesicles). For ganglioside Gd1a, the activity on Triton X-100 mixed micelles and on mixed vesicles was even greater (3- and 6-fold respectively) than that displayed on Gd1a lipid-free carbohydrate. With each of the used gangliosides the apparent Km values were very similar values for homogeneous micelles and vesicular dispersions, but showed marked increases for Triton X-100 mixed micelles, approaching the values exhibited by reference oligosaccharides. Triton X-100 micelles and phosphatidylcholine vesicles did not appreciably alter the kinetics of sialidase action on 3′-sialosyl-lactose and on Gd1a lipid-free carbohydrate, indicating that the above effects are dependent on the intrinsic characteristics of the membrane-like systems containing gangliosides. 相似文献
9.
Takamichi Yamada Shoji Tsuji Toshio Ariga Tadashi Miyatake 《Biochimica et Biophysica Acta (BBA)/General Subjects》1983,755(1):106-111
We analyzed the subcellular localization of sialidases in human lymphocytes from a patient with adult type sialidosis with partial β-galactosidase deficiency and normal controls. Sialidase activities were measured with α,2 → 3 NeuAc-lactitol, 4-methylumbelliferyl-NeuAc and GM3 ganglioside as substrates. Sialidases in the lysosomes were sonication-labile and hydrolyzed mainly hydrophilic substrates such as NeuAc-lactitol and 4-methylumbelliferyl-NeuAc, but hydrolyzed subsidiarily GM3 ganglioside. On the other hand, sialidases in the plasma membrane were sonication-stable and hydrolyzed both hydrophilic substrates and GM3 ganglioside. In sialidosis with partial β-galactosidase deficiency, the sialidases of the lysosomes showed 3–5% activity toward hydrophilic substrates and 25% activity toward GM3 ganglioside as compared with sialidase activities of the controls. However, there are no differences in the activities of the sialidases in the plasma membrane. These results demonstrate that the essential defect in this disease is the deficiency of a lysosomal sialidase. 相似文献
10.
Sialidases cleave off sialic acid residues from the oligosaccharide chain of gangliosides in their catabolic pathway while sialyltransferases transfer sialic acid to the growing oligosaccharide moiety in ganglioside biosynthesis. Ganglioside GM3 is a common substrate for both types of enzymes, for sialidase acting on ganglioside GM3 as well as for ganglioside GD3 synthase. Therefore, it is possible that both enzymes recognize similar structural features of the sialic acid moiety of their common substrate, ganglioside GM3. Based on this idea we used a variety of GM3 derivatives as glycolipid substrates for a bacterial sialidase (Clostridium perfringens) and for GD3 synthase (of rat liver Golgi vesicles). This study revealed that those GM3 derivatives that were poorly degraded by sialidase also were hardly recognized by sialyltransferase (GD3 synthase). This may indicate similarities in the substrate binding sites of these enzymes. 相似文献
11.
Guiliano Gazzotti Sandro Sonnino Riccardo Ghidoni Paolo Orlando Guido Tettamanti 《Glycoconjugate journal》1984,1(2):111-121
Gangliosides GM2, GM1 and GD1b were radiolabelled at C-6 of the terminal galactose orN-acetylgalactosamine by the galactose oxidase/[3H]NaBH4 method; gangliosides GM2, GM1, Fuc-GM1 and GD1a were radiolabelled at C-3 of the long chain base by the 2,3-dichloro-5,6-dicyanobenzoquinone/[3H]NaBH4 method.By application of an original HPLC procedure, eight different molecular species were prepared from each labelled ganglioside. Each of these species was characterized by the presence of one of the following long chain bases:erythro C18 sphingosine,threo C18 sphingosine,erythro C18 sphinganine,threo C18 sphinganine,erythro C20 sphingosine,threo C20 sphingosine,erythro C20 sphinganine andthreo C20 sphinganine.From GD1b only the species containing theerythro forms of long chain bases were obtained.The individual molecular species were more than 99% homogeneous and had a radiopurity better than 99%. The molecular species of the same ganglioside, radiolabelled at C-3 of the long chain base, had identical specific radioactivity, namely 1.17, 1.25, 0.85 and 1.28 Ci/mmol for GM2, GM1, Fuc-GM1 and GD1a respectively. The molecular species of the same ganglioside, radiolabelled at C-6 of terminal galactose orN-acetylgalactosamine, had similar specific radioactivity, namely 1.34–1.40, 1.44–1.51, 1.37–1.44 Ci/mmol for GM2, GM1 and GD1b respectively. 相似文献
12.
High-performance thin-layer chromatography and densitometric determination of brain ganglioside compositions of several species. 总被引:34,自引:0,他引:34
Improved resolution of complex brain ganglioside mixtures was achieved by high-performance thin-layer chromatography. The percentage distribution of individual gangliosides was then determined by direct densitometric seanning, employing a transmittance mode, of the resorcinol-positive spots on the plate. As little as 90 pmol (29 ng) of lipid-bound sialic acid could be detected with a good signal-to-noise ratio. A linear detector response was observed up to 3.0 μg of lipid-bound sialic acid. The brain white matter ganglioside patterns of eight animal species, including human, chimpanzee, monkey, chicken, bovine, sheep, and pig, were examined in detail. In addition, human brain gray matter, rat cerebral, rat brain gray matter, and rat cerebellar ganglioside patterns were also studied. Ganglioside GM4 (G7) was found to be one of the major components in primate and chicken brain white matter, but it represented only a minor ganglioside in other species. Other major gangliosides in all brain samples studied were GM1, GD1a, GD1b, and GT1b. GM1 was more abundant in white matter than in gray matter. GT1a, a recently discovered ganglioside species, was found in all species examined, but was most abundant in the rat cerebellum. The latter source also contained high proportions of GT1b and GQ1b. 相似文献
13.
A hallmark of the common Alzheimer's disease (AD) is the pathological conversion of its amphiphatic amyloid-β (Aβ) peptide into neurotoxic aggregates. In AD patients, these aggregates are often found to be tightly associated with neuronal GM1 ganglioside lipids, suggesting an involvement of GM1 not only in aggregate formation but also in neurotoxic events. Significant interactions were found between micelles made of newly synthesized fluorescent GM1 gangliosides labeled in the polar headgroup or the hydrophobic chain and Aβ(1-40) peptide labeled with a BODIPY-FL-C1 fluorophore at positions 12 and 26, respectively. From an analysis of energy transfer between the different fluorescence labels and their location in the molecules, we were able to place the Aβ peptide inside GM1 micelles, close to the hydrophobic-hydrophilic interface. Large unilamellar vesicles composed of a raftlike GM1/bSM/cholesterol lipid composition doped with labeled GM1 at various positions also interact with labeled Aβ peptide tagged to amino acids 2 or 26. A faster energy transfer was observed from the Aβ peptide to bilayers doped with 581/591-BODIPY-C11-GM1 in the nonpolar part of the lipid compared with 581/591-BODIPY-C5-GM1 residing in the polar headgroup. These data are compatible with a clustering process of GM1 molecules, an effect that not only increases the Aβ peptide affinity, but also causes a pronounced Aβ peptide penetration deeper into the lipid membrane; all these factors are potentially involved in Aβ peptide aggregate formation due to an altered ganglioside metabolism found in AD patients. 相似文献
14.
15.
New fluorophore-labelled GM1 gangliosides have been synthesised and spectroscopically characterised. Spectroscopically different BODIPY groups were covalently linked, specifically to either the polar or the hydrophobic part of the ganglioside molecule. The absorption and fluorescence spectroscopic properties are reported for 564/571-BODIPY- and 581/591-BODIPY-labelled GM1. Each of the different BODIPY groups is highly fluorescent and depolarisation experiments provide molecular information about the spatial distribution in lipid bilayers, as well as order and dynamics. From experiments performed on two spectroscopically different BODIPY:s, specific interactions can be revealed by monitoring the rate/efficiency of donor-acceptor electronic energy transfer. Systems of particular interest for applying these probes are e.g. mixtures of lipids, and peptides/proteins interacting with lipid membranes. 相似文献
16.
Mucolipidosis IV (ML IV) is an inherited lysosomal disorder for which the primary biochemical defect has not been identified. In order to detect any defect in glycosphingolipid metabolism, we have examined the metabolism of sphingosine-labeled (3H)GM2 in situ in fibroblasts from patients diagnosed with ML IV. Fibroblasts were exposed for 10 days in medium containing (3H)GM2 (15 uM; Sp. Act. 35000 cpm/nmole), washed, harvested and analyzed for radioactivity in extracted lipids. Control cells metabolized about half of the internalized ganglioside, mostly to ceramide. In ML IV fibroblasts, 70–80% of the cellular radioactivity was present as GM2 indicating reduced degradation. This is not as severe as in GM2 gangliosidosis as a small amount of GM2 was metabolized in ML IV cells to ceramide. Since there is no defect in the lysosomal enzyme profile in these cells, it is possible that an abnormality in the translocation of membrane constituents to the lysosomes may explain the slower ganglioside metabolism. 相似文献
17.
Staphylococcus pseudintermedius is a major cause of skin and soft tissue infections in companion animals and has zoonotic potential. Additionally, methicillin-resistant S. pseudintermedius (MRSP) has emerged with resistance to virtually all classes of antimicrobials. Thus, novel treatment options with new modes of action are required. Here, we investigated the antimicrobial activity of six synthetic short peptides against clinical isolates of methicillin-susceptible and MRSP isolated from infected dogs. All six peptides demonstrated potent anti-staphylococcal activity regardless of existing resistance phenotype. The most effective peptides were RRIKA (with modified C terminus to increase amphipathicity and hydrophobicity) and WR-12 (α-helical peptide consisting exclusively of arginine and tryptophan) with minimum inhibitory concentration50 (MIC50) of 1 µM and MIC90 of 2 µM. RR (short anti-inflammatory peptide) and IK8 “D isoform” demonstrated good antimicrobial activity with MIC50 of 4 µM and MIC90 of 8 µM. Penetratin and (KFF)3K (two cell penetrating peptides) were the least effective with MIC50 of 8 µM and MIC90 of 16 µM. Killing kinetics revealed a major advantage of peptides over conventional antibiotics, demonstrating potent bactericidal activity within minutes. Studies with propidium iodide and transmission electron microscopy revealed that peptides damaged the bacterial membrane leading to leakage of cytoplasmic contents and consequently, cell death. A potent synergistic increase in the antibacterial effect of the cell penetrating peptide (KFF)3K was noticed when combined with other peptides and with antibiotics. In addition, all peptides displayed synergistic interactions when combined together. Furthermore, peptides demonstrated good therapeutic indices with minimal toxicity toward mammalian cells. Resistance to peptides did not evolve after 10 passages of S. pseudintermedius at sub-inhibitory concentration. However, the MICs of amikacin and ciprofloxacin increased 32 and 8 fold, respectively; under similar conditions. Taken together, these results support designing of peptide-based therapeutics for combating MRSP infections, particularly for topical application. 相似文献
18.
Formation and turnover of myelin ganglioside 总被引:7,自引:6,他引:1
K Suzuki 《Journal of neurochemistry》1970,17(2):209-213
—In young adult rats, the formation and turnover of GM1-ganglioside in myelin were compared with the formation and turnover of GM1-ganglioside in whole brain and of total lipids in whole brain and myelin, after injection of d-[1-14C]glucosamine. During the first 24 hr after injection, the specific activity of GM1-ganglioside in myelin was less than 25 per cent of that of GM1-ganglioside in whole brain. The specific activity of ganglioside in whole brain was maximal at 24 hr and then declined steadily during the next 3 months, whereas the specific activity of GM1-ganglioside in myelin continued to increase and did not reach a peak until about one month after injection, by which time its specific activity had increased five-fold. Consequently, the specific activity of GM1-ganglioside in myelin was 50 per cent higher than ganglioside in whole brain after one month. These differences in the formation and turnover of GM1-ganglioside in myelin and of whole brain are similar to those of other lipids of myelin and of whole brain, indicating that the metabolic activity of myelin ganglioside is similar to myelin lipids, but differs from whole brain lipids or whole brain gangliosides. These data provide additional evidence that ganglioside in myelin is an intrinsic constituent of the myelin sheath. GT1 (G1), GD1b, (G2), GD1a (G3), GM1 (G4), GM2 (G5), GM3 (G6). 相似文献
19.
Saki Itonori Kazuya Hidari Yutaka Sanai Masaru Taniguchi Yoshitaka Nagai 《Glycoconjugate journal》1989,6(4):551-560
The effect of the chain length of the fatty acid residue of the ceramide moiety of ganglioside GM3 on the binding ability of monoclonal antibody M2590, which is specific for the carbohydrate structure of GM3-ganglioside, was examined by means of a direct binding assay on thin layer chromatography plates (TLC immunostaining) and a quantitative enzyme-linked immunosorbent assay (ELISA). Derivatives of GM3 with a long fatty acid chain reacted with the M2590 antibody, but those with a short fatty acid chain showed no reaction in either assay system. These results suggested that the acyl fatty acid moiety of the ganglioside played an important role in the formation or maintenance of the antigenic structure of the carbohydrate moiety of the ganglioside. 相似文献
20.
Seandean Lykke Harwood Nadia Sukusu Nielsen Khang Diep Kathrine Tejlgrd Jensen Peter Kresten Nielsen Kazuhiro Yamamoto Jan J. Enghild 《The Journal of biological chemistry》2021,297(1)
Human α2-macroglobulin (A2M) is an abundant protease inhibitor in plasma, which regulates many proteolytic processes and is involved in innate immunity. A2M’s unique protease-trapping mechanism of inhibition is initiated when a protease cleaves within the exposed and highly susceptible “bait region.” As the wild-type bait region is permissive to cleavage by most human proteases, A2M is accordingly a broad-spectrum protease inhibitor. In this study, we extensively modified the bait region in order to identify any potential functionally important elements in the bait region sequence and to engineer A2M proteins with restrictive bait regions, which more selectively inhibit a target protease. A2M in which the bait region was entirely replaced by glycine-serine repeats remained fully functional and was not cleaved by any tested protease. Therefore, this bait region was designated as the “tabula rasa” bait region and used as the starting point for further bait region engineering. Cleavage of the tabula rasa bait region by specific proteases was conveyed by the insertion of appropriate substrate sequences, e.g., basic residues for trypsin. Screening and optimization of tabula rasa bait regions incorporating matrix metalloprotease 2 (MMP2) substrate sequences produced an A2M that was specifically cleaved by MMPs and inhibited MMP2 cleavage activity as efficiently as wild-type A2M. We propose that this approach can be used to develop A2M-based protease inhibitors, which selectively inhibit target proteases, which might be applied toward the clinical inhibition of dysregulated proteolysis as occurs in arthritis and many types of cancer. 相似文献