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PubMed2000

Developments in the assessment of glomerular filtration rate.

The assessment of the glomerular filtration rate (GFR) is the most commonly used test of renal function. The accepted reference procedure employs an exogenous clearance marker whilst the most popular test is that of serum or plasma creatinine. All of these tests have limitations, although the surrogate endogenous markers are the most practical. Cystatin C, a low molecular weight protein which can be measured by light scattering immunoassay, possesses many of the attributes required of the ideal GFR marker. Data on reference ranges indicate that circulating cystatin C levels reflect the variation in GFR throughout life and the marker demonstrates a better correlation with the reference procedure than serum creatinine.

Biomarkers↗
PubMed2001

Dynamics of brain-derived proteins in cerebrospinal fluid.

BACKGROUND: The recent theory of blood-cerebrospinal fluid (CSF) barrier function and dysfunction connects molecular flux and CSF flow rate. A reduced CSF flow rate is sufficient to account for the observed hyperbolic relation between different blood-derived protein concentrations in CSF in cases of a blood-CSF barrier dysfunction. METHODS: The dynamics of brain-derived proteins in CSF are investigated with reference to the CSF flow rate measured by CSF/serum albumin concentration quotient. RESULTS: Proteins from neurons or glial cells, tau protein, neuron-specific enolase, S-100 protein, all enter CSF primarily in the ventricular and cisternal space. Their concentration between normal ventricular and lumbar CSF is decreasing (in contrast to blood-derived proteins), and in the case of pathologically decreasing CSF flow rate, the concentration in lumbar CSF remains invariantly constant. Concentrations of the primarily leptomeningeal proteins, beta-trace protein and cystatin C, increase between normal ventricular and lumbar CSF, and in the case of pathologically decreased CSF flow rate they increase linearly in lumbar CSF (concentrations of blood-derived proteins increase non-linearly). CONCLUSIONS: A satisfactory physiological explanation can now be given for the dynamics of proteins in CSF consisting of both brain- and blood-derived fractions (transthyretin, soluble intercellular adhesion molecule (s-ICAM)), as well as the disputed decrease of leptomeningeal protein concentrations (beta-trace protein, cystatin C) in cases of bacterial meningitis is also explained. The biophysical treatment of dynamics in the ventricular and lumbar CSF extends the new theory and shows that CSF flow rate is the most relevant parameter for understanding the pathological changes of both blood- and brain-derived proteins in CSF. The impact on diagnosis of neuro-degenerative diseases is discussed.

Albumins↗
PubMed2003

Crystal structure of Stefin A in complex with cathepsin H: N-terminal residues of inhibitors can adapt to the active sites of endo- and exopeptidases.

Binding of cystatin-type inhibitors to papain-like exopeptidases cannot be explained by the stefin B-papain complex. The crystal structure of human stefin A bound to an aminopeptidase, porcine cathepsin H, has been determined in monoclinic and orthorhombic crystal forms at 2.8A and 2.4A resolutions, respectively. The asymmetric unit of each form contains four complexes. The structures are similar to the stefin B-papain complex, but with a few distinct differences. On binding, the N-terminal residues of stefin A adopt the form of a hook, which pushes away cathepsin H mini-chain residues and distorts the structure of the short four residue insertion (Lys155A-Asp155D) unique to cathepsin H. Comparison with the structure of isolated cathepsin H shows that the rims of the cathepsin H structure are slightly displaced (up to 1A) from their position in the free enzyme. Furthermore, comparison with the stefin B-papain complex showed that molecules of stefin A bind about 0.8A deeper into the active site cleft of cathepsin H than stefin B into papain. The approach of stefin A to cathepsin H induces structural changes along the interaction surface of both molecules, whereas no such changes were observed in the stefin B-papain complex. Carboxymethylation of papain seems to have prevented the formation of the genuine binding geometry between a papain-like enzyme and a cystatin-type inhibitor as we observe it in the structure presented here.

Animals↗
PubMed1997

Giant cell arteritis in association with cerebral amyloid angiopathy: immunohistochemical and molecular studies.

Giant cell arteritis (GCA) usually manifests as a transmural vascular infiltrate of mononuclear and multinucleated giant cells (MNGC). We describe six patients with GCA associated with severe cerebral amyloid angiopathy (CAA), all with cerebral hemorrhage or varying degrees of cerebral infarct, and histological evidence of Alzheimer's disease (cortical CAA often predominating over senile plaques and neurofibrillary tangles). One case showed mostly cortical involvement (with old microhemorrhages), and the others were primarily leptomeningeal (with involvement of the underlying cortex and extensive encephalomalacia of adjacent brain). Many vessels with CAA exhibited a pronounced adventitial and perivascular infiltrate of lymphocytes, histiocytes, and MNGC. Immunohistochemical staining showed deposition of beta/A4 peptide primarily in the thickened media of CAA vessels, and within the cytoplasm of MNGC--suggesting phagocytosis of insoluble peptide. Cystatin C antibody stained vascular amyloid and diffusely highlighted astrocytic and MNGC cytoplasm. HAM56-positive macrophages were frequently seen around amyloid-laden vessels. Anti-smooth muscle actin immunohistochemistry suggests the occurrence of medial destruction by amyloid, with relative preservation of intimal cells. Ultrastructural studies performed in one case confirmed the presence of intracytoplasmic amyloid in MNGC. The GCA seen in these cases of CAA most likely represents a foreign body response to amyloid proteins, causing secondary destruction of the vessel wall. DNA from brain tissues of five affected patients was examined to assess whether mutations were present in exon 17 of the APP gene or exon 2 of the cystatin C gene, a finding that might explain the foreign body giant cell response to amyloid proteins in these cases. However, restriction fragment mapping of amplified gene segments showed that previously described mutations were not present in these cases.

Actins↗
PubMed1998

Developmental regulation of invariant chain proteolysis controls MHC class II trafficking in mouse dendritic cells.

Dendritic cells (DCs) developmentally regulate their capacity for antigen presentation by controlling the transport and surface expression of MHC class II molecules. These events reflect a developmental regulation of invariant (Ii) chain cleavage, most likely by the cysteine protease cathepsin S. In immature DCs, inefficient Ii chain cleavage due to low cathepsin S activity leads to the transport of class II-Ii chain complexes to lysosomes, while in mature DCs, elevated cathepsin S activity results in efficient delivery of class II alphabeta dimers to the plasma membrane. Cathepsin S is not controlled transcriptionally but by a novel mechanism involving alterations in the expression and localization of an endogenous cathepsin S inhibitor cystatin C. Thus, the ratio of cystatin C to cathepsin S in developing DCs helps to determine the fate of newly synthesized MHC class II molecules.

Animals↗
PubMed2000

Homocysteine and endogenous markers of renal function in type 2 diabetic patients without coronary heart disease.

The aim of this study was to assess parameters of renal function and other determinants of plasma homocysteine in type 2 diabetic patients without coronary heart disease (CHD). Fasting plasma homocysteine, serum cystatin C and serum creatinine were determined in 183 (75 men, 108 women) Type 2 diabetic patients without clinical evidence of CHD. Creatinine clearance was calculated and parameters such as blood pressure, body mass index (BMI), and glycated haemoglobin (HbA(1c)) were assessed. The urine albumin:creatinine ratio was used to classify patients as normo-, micro- or macroalbuminuric. One hundred and ten patients were normoalbuminuric, 67 patients were microalbuminuric and six patients were macroalbuminuric. There was no statistically significant difference in plasma homocysteine concentration between patients with normoalbuminuria and microalbuminuria. There was a trend towards increasing plasma homocysteine with decreasing glomerular filtration rate (GFR) (r=-0.46; P<0.0001). There was statistically significant correlation between plasma homocysteine and age (r=0.37), serum cystatin C (r=0.47), and serum creatinine (r=0.56). Plasma homocysteine concentration was significantly higher in patients with BMI<30 kg/m(2) and showed significant inverse correlation with weight (r=-0.16; P=0.03) and body mass index (r=-0.24; P=0.001). Homocysteine and serum creatinine were significantly higher in males than females and higher in smokers than non smokers but was not associated with glycemic control and duration of diabetes. In conclusion, elevated homocysteine concentration in patients with type 2 DM without CHD is related to age, gender, smoking, BMI and GFR. Follow up studies will provide further information on the association between hyperhomocysteinemia and the development of cardiovascular disease.

Albuminuria↗
PubMed2001

Spinal cord genes enriched in rat dorsal horn and induced by noxious stimulation identified by subtraction cloning and differential hybridization.

Persistent nociceptive input increases neuronal excitability and induces a program of gene expression in the dorsal spinal cord. The alteration in gene expression commences with phosphorylation and induction of immediate early genes and proceeds to target genes. Only a few target genes have been identified as yet. The present report uses a polymerase chain reaction-based subtraction cloning procedure to obtain an "anatomically focused" complementary DNA library enriched in transcripts related to sensory spinal cord (rat dorsal horn minus ventral horn). A subset of clones from this library (n=158) was screened to verify dorsal horn enrichment and to identify those regulated by carrageenan-induced peripheral inflammation. Molecular classes which displayed enriched expression included a proto-oncogene not previously associated with sensory processes, two regulators of the Rho/Rac pathway which controls cell shape, and three genes involved in cytoskeletal regulation and scaffolding. Additional transcripts coded for proteins involved in intercellular communication or intracellular function. Within the set of 158 transcripts, one known and two unknown genes were induced by persistent noxious input. The known gene codes for the secreted cysteine proteinase inhibitor, cystatin C, suggesting that modulation of extracellular proteolytic activity occurs. Since it is secreted, cystatin C may also provide a cerebrospinal fluid bio-marker for persistent pain states. Using a combined anatomical and functional approach, we have extended the molecular repertoire of genes expressed and induced in second-order neurons or supporting glial cells in several new directions, with particular emphasis on regulation of cell morphology and plasma membrane dynamics. Some of these proteins reveal new pathways for information signaling in the sensory half of the spinal cord and require further research to understand their role in the adult spinal cord. The induced genes may provide new molecular targets for therapeutic development and provide new probes for investigating the dynamic state of cellular activity that occurs during persistent pain states.

Animals↗
PubMed2000

FGF-2-responsive neural stem cell proliferation requires CCg, a novel autocrine/paracrine cofactor.

We have purified and characterized a factor, from the conditioned medium of neural stem cell cultures, which is required for fibroblast growth factor 2's (FGF-2) mitogenic activity on neural stem cells. This autocrine/paracrine cofactor is a glycosylated form of cystatin C (CCg), whose N-glycosylation is required for its activity. We further demonstrated that, both in vitro and in vivo, neural stem cells undergoing cell division are immunopositive for cystatin C. Finally, we showed in vivo functional activity of CCg by demonstrating that the combined delivery of FGF-2 and CCg to the adult dentate gyrus stimulated neurogenesis. We propose that the process of neurogenesis is controlled by the cooperation between trophic factors and autocrine/paracrine cofactors, of which CCg is a prototype.

Animals↗
PubMed1995

Crystal structure of glycyl endopeptidase from Carica papaya: a cysteine endopeptidase of unusual substrate specificity.

Glycyl endopeptidase is a cysteine endopeptidase of the papain family, characterized by specificity for cleavage C-terminal to glycyl residues only and by resistance to inhibition by members of the cystatin family of cysteine proteinase inhibitors. Glycyl endopeptidase has been crystallized from high salt with a substrate-like inhibitor covalently bound to the catalytic Cys 25. The structure has been solved by molecular replacement with the structure of papain and refined at 2.1 A to an R factor of 0.196 (Rfree = 0.258) with good geometry. The structure of the S1 substrate binding site of glycyl endopeptidase differs from that of papain by the substitution of glycines at residues 23 and 65 in papain, with glutamic acid and arginine, respectively, in glycyl endopeptidase. The side chains of these residues form a barrier across the binding pocket, effectively excluding substrate residues with large side chains from the S1 subsite. The constriction of this subsite in glycyl endopeptidase explains the unique specificity of this enzyme for cleavage after glycyl residues and is a major component of its resistance to inhibition by cystatins.

Amino Acid Sequence↗
PubMed1999

Human cathepsin X: A cysteine protease with unique carboxypeptidase activity.

Cathepsin X is a novel cysteine protease which was identified recently from the EST (expressed sequence tags) database. In a homology model of the mature cathepsin X, a unique three residue insertion between the Gln22 of the oxyanion hole and the active site Cys31 was found to be located in the primed region of the binding cleft as part of a surface loop corresponding to residues His23 to Tyr27, which we have termed the "mini-loop". From the model, it became apparent that this distinctive structural feature might confer exopeptidase activity to the enzyme. To verify this hypothesis, human procathepsin X was expressed in Pichia pastoris and converted to mature cathepsin X using small amounts of human cathepsin L. Cathepsin X was found to display excellent carboxypeptidase activity against the substrate Abz-FRF(4NO(2)), with a k(cat)/K(M) value of 1.23 x 10(5) M(-)(1) s(-)(1) at the optimal pH of 5.0. However, the activity of cathepsin X against the substrates Cbz-FR-MCA and Abz-AFRSAAQ-EDDnp was found to be extremely low, with k(cat)/K(M) values lower than 70 M(-)(1) s(-)(1). Therefore, cathepsin X displays a stricter exopeptidase activity than cathepsin B. No inhibition of cathepsin X by cystatin C could be detected up to a concentration of 4 microM of inhibitor. From a model of the protease complexed with Cbz-FRF, the bound carboxypeptidase substrate is predicted to establish a number of favorable contacts within the cathepsin X binding site, in particular with residues His23 and Tyr27 from the mini-loop. The presence of the mini-loop restricts the accessibility of cystatin C as well as of the endopeptidase and MCA substrates in the primed subsites of the protease. The marked structural and functional differences of cathepsin X relative to other members of the papain family of cysteine proteases will be of great value in designing specific inhibitors useful as research tools to investigate the physiological and potential pathological roles of this novel enzyme.

Carboxypeptidases↗
PubMed2006

Active cathepsins B, H, K, L and S in human inflammatory bronchoalveolar lavage fluids.

BACKGROUND INFORMATION: Chronic inflammation and tissue remodelling result from an imbalance between proteolytic enzymes and their inhibitors in the lungs in favour of proteolysis. While many studies have examined serine proteases (e.g. cathepsin G and neutrophil elastase) and matrix metalloproteases, little is known about the role of papain-like CPs (cysteine proteases). The present study focuses on the thiol-dependent cathepsins (CPs) and their specific cystatin-like inhibitors [CPIs (CP inhibitors)] in human inflammatory BALFs (BAL fluids, where BAL stands for broncho-alveolar lavage). RESULTS: Cathepsins B, K and S found were mostly zymogens, whereas cathepsins H and L were predominantly in their mature forms. Little immunoreactive cystatin C was found and the high- and low-molecular-mass ('weight') kininogens were extensively degraded. The BALF procathepsins B and L could be activated autocatalytically, indicating that alveolar fluid pro-CPs are reservoirs of mature enzymes. Hydrolysis patterns of 7-amino-4-methylcoumarin-derived peptide substrates showed that extracellular alveolar CPs remain proteolytically active, and that cathepsins B and L are the most abundant thiol-dependent endoproteases. The CP/CPI balance was significantly tipped in favour of cathepsins (3- or 5-fold), as confirmed by the extensive CP-dependent degradation of exogenous kininogens by BALFs. CONCLUSIONS: Although their importance for inflammation remains to be clarified, the presence of active cathepsins L, K and S suggests that they contribute to the extracellular breakdown of the extracellular matrix.

Bronchoalveolar Lavage Fluid↗
PubMed1989

Beta-adrenergic induction of a cysteine-proteinase-inhibitor mRNA in rat salivary glands.

Transcripts encoding the cysteine-proteinase inhibitor rat cystatin S are induced in submandibular and parotid glands by the beta-adrenergic agonist isoproterenol (isoprenaline). High levels of cystatin S mRNA persist in glands of chronically treated animals for 6 days after discontinuation of the catecholamine, indicating a long half-life of the mRNA. Post-transcriptionally the size of the mRNA decreases, owing to a shortening of the poly(A) tail.

Animals↗
PubMed2003

Antihypertensive treatment and homocysteine concentrations.

Thiazides and angiotensin-converting enzyme (ACE) inhibitors are first-choice drugs for lowering elevated blood pressure and hence risk of cardiovascular disease. Homocysteine (tHcy) is another and independent cardiovascular risk factor and has been reported to be elevated in patients on antihypertensive therapy. As these studies reported only associations, a preliminary, randomized, prospective treatment study was performed in 40 hypertensive patients. We investigated the major determinants of tHcy concentrations after treatment with hydrochlorothiazide (HCT) or captopril: vitamins B6, B12, folic acid, and creatinine and cystatin C as parameters of renal function. A total of 21 Patients were treated with HCT and 19 with captopril, for, respectively, 31 and 29 days. HCT, but not captopril, raised tHcy by 16% (P =.003) and also creatinine and cystatin C (P =.025 and P =.004, respectively). This tHcy increase may offset the desired cardioprotection conferred by lowering the blood pressure.

Aged↗
PubMed1998

Hyperamylasemia after cardiopulmonary bypass: pancreatic cellular injury or impaired renal excretion of amylase?

BACKGROUND: Postoperative hyperamylasemia and even acute pancreatitis are associated with coronary artery bypass grafting (CABG). The mechanism of hyperamylasemia and pancreatic acinar cell damage was studied in 20 patients undergoing CABG. METHODS: Serial blood and urine samples at eight time points before, during, and 24 hours after the CABG were collected. Salivary and pancreatic isoamylases, the fractional clearance of isoamylases (i.e., relative to creatinine clearance), pancreatic phospholipase A2 (a specific serum marker of pancreatic acinar cell injury), and cystatin C (a sensitive marker of glomerular filtration rate) were measured. RESULTS: Mild serum hyperamylasemia (300 to 1000 units/L) was found in 11 of 20 (55%) and severe (> 1000 units/L) in 6 of 20 (30%) patients with no signs of clinical acute pancreatitis. Hyperamylasemia occurred from 6 to 24 hours after the CABG and was mainly caused by pancreatic isoamylase. Serum pancreatic phospholipase A2 concentration remained unchanged, which excludes acinar cell damage. Although renal glomerular filtration was normal during CABG as measured by serum cystatin C and creatinine clearance, the fractional clearance of isoamylases decreased. CONCLUSIONS: The decreased rate of excretion into urine, rather than pancreatic cellular damage, is the major source of hyperamylasemia after CABG.

Amylases↗
PubMed2004

High prevalence of hyperhomocysteinemia related to folate deficiency and the 677C-->T mutation of the gene encoding methylenetetrahydrofolate reductase in coastal West Africa.

BACKGROUND: Moderate hyperhomocysteinemia is a risk for neural tube defect and neurodegenerative and vascular diseases and has nutritional, metabolic, and genetic determinants. Its prevalence in sub-Saharan Africa remains unknown. OBJECTIVE: Our goal was to evaluate the prevalence of hyperhomocysteinemia and the influence of nutritional, metabolic, and genetic determinants in savanna and coastal regions of Togo and Benin. DESIGN: Volunteers were recruited from coastal (C groups; n = 208) and savanna (S group; n = 68) regions. Vitamin B-12, folate, total homocysteine (tHcy), cystatin C (a marker of glomerular filtration), and inflammatory and nutritional protein markers were measured in plasma, and the methylenetetrahydrofolate reductase (MTHFR) 677C-->T and 1298A--> C polymorphisms and the methionine synthase 2756A-->G polymorphism were examined in genomic DNA. RESULTS: Moderate hyperhomocysteinemia (tHcy > 15 micromol/L) was recorded in 62.3% and 29.4% of the subjects from the coast and savanna, respectively (P < 0.0001). A histogram distribution of tHcy in the coastal groups showed a distinct group, C2 (15% of the total group), with tHcy > 28 micro mol/L. Folate < 6.75 nmol/L (lower quartile) and MTHFRCT/TT genotype were the 2 main risk factors for moderate hyperhomocysteinemia in the whole population [odds ratios: 5.3 (95% CI: 2.5, 11.2; P < 0.0001) and 4.9 (1.6, 14.8; P = 0.0048), respectively] and in the C2 group [odds ratios: 15.9 (4.5, 56.8; P < 0.0001) and 9.0 (2.3, -35.2; P = 0.0017), respectively]. Cystatin C was another potent risk factor in the C2 group. CONCLUSION: A high prevalence of hyperhomocysteinemia in coastal West Africa, related to folate concentrations and the MTHFR 677 T allele, suggests the need to evaluate the influence of hyperhomocysteinemia on disease in this area.

Adult↗
PubMed2006

Fetuin-A and kidney function in persons with coronary artery disease--data from the Heart and Soul Study.

BACKGROUND: Fetuin-A is a serum protein that inhibits ectopic vascular calcification and is present in lower concentrations in end-stage renal disease than in healthy controls. Whether fetuin-A concentrations are also lower in the setting of mild-to-moderate chronic kidney disease (CKD) is unknown. METHODS: We evaluated the associations of several parameters of kidney function including measured 24 h urinary creatinine clearance (CrCl), estimated glomerular filtration rate (GFR) by the Mayo Clinic quadratic GFR equation (qGFR), serum cystatin-C concentrations, and urinary albumin-to-creatinine ratio with serum fetuin-A concentrations in 970 outpatients with coronary artery disease. We used general linear models to determine the adjusted mean fetuin-A concentrations within each kidney function category. RESULTS: The mean age of the study sample was 67 years, 82% were male, 71% had hypertension and 26% had diabetes mellitus. In adjusted analysis, we observed no significant differences in mean fetuin-A concentrations across groups defined by CrCl, qGFR, or albumin-to-creatinine ratio groups. For example, adjusted mean fetuin-A concentrations were 0.66 g/l in participants with CrCl > 90, 60-90 and 45-60 ml/min/1.73 m(2), and 0.65 g/l in participants with CrCl < 45 ml/min/1.73 m(2). Higher serum cystatin-C (indicating worse kidney function) was associated with higher adjusted mean serum fetuin-A concentrations (lowest quartile 0.62 g/l, highest quartile 0.68 g/l; P for trend <0.001). CONCLUSIONS: Among ambulatory patients with coronary artery disease, there is no evidence that mild-to-moderate CKD is associated with lower concentrations of serum fetuin-A compared with persons with normal renal function. The mechanisms explaining the association between CKD and vascular calcification remain elusive.

Aged↗
PubMed2006

Insulin resistance and the progression of IgA glomerulonephritis.

BACKGROUND: IgA glomerulonephritis (IgAGN) has a highly variable prognosis with 15-40% of patients progressing to end-stage renal disease. Hypertension, proteinuria and renal insufficiency are risk factors associated with poor prognosis. The role of insulin resistance is unclear in IgAGN. METHODS: From a retrospective cohort of IgAGN patients, a total of 174 patients (104 males) were invited for two visits at the clinic, 11 and 16 years (median times) after IgAGN was diagnosed in renal biopsy. Of all the patients, 63% had been diagnosed at least 10 years before the first visit. Progressive disease was defined as cystatin-C exceeding normal limits and showing over 20% elevation between the first and second visits, or kidney transplantation or start of dialysis. Plasma insulin, homeostasis model assessment of insulin resistance (HOMA-IR) index and cystatin-C were obtained for analysis from 118 patients. RESULTS: IgAGN was progressive in 19.5% of the patients on the second visit. Insulin level and HOMA-IR of the first visit showed significant association with the progression of IgAGN (P = 0.019 and 0.005, respectively). CONCLUSIONS: Our results show that in addition to the known risk factors age, hypertension, proteinuria and hyperuricaemia, plasma insulin level and calculated HOMA-IR are associated with the progression of IgAGN.

Adolescent↗
PubMed1995

Modification of S1 subsite specificity in the cysteine protease cathepsin B.

Cysteine proteases of the papain family generally exhibit broad P1 specificity. A notable exception is papaya proteinase IV (PPIV), which only accepts Gly at this position. In all other cysteine proteases the S1 subsite residues 23 and 65 (papain numbering) are absolutely conserved as Gly, while in PPIV they are replaced by Glu and Arg, respectively. These differences appear to underlie both PPIV specificity and its resistance to inhibition by cystatins. To test this hypothesis, the equivalent residues (Gly27 and Gly73) in the mammalian cysteine protease cathepsin B were changed to Glu and Arg, respectively. Relative to the wild-type enzyme, the Gly27Glu and Gly73Arg mutants showed a drastic reduction in activity with substrates containing a P1 Arg. In contrast, substrates having a Gly residue in P1 were hydrolyzed effectively. The double mutant (Gly27Glu:Gly73Arg) exhibited no detectable activity against any substrate studied. Inhibition of the Gly73Arg mutant by E-64 [1-(L-trans-epoxysuccinyl-L-leucylamino)-4-guanidinobutane] was found to be similar to that of the wild-type enzyme. In contrast, inhibition by cystatin C exhibited a 20,000-fold reduction. These results demonstrate the dramatic influence of side chains at sequence locations 27 and 73 on the S1 subsite specificity of cysteine proteases.

Animals↗