Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.4 (trypsin)
 42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Rabbit serum amyloid A (SAA) protein was isolated from acute-phase serum by ultracentrifugation, molecular seive chromatography, and ion-exchange chromatography. The complete amino acid sequence of the protein was established by sequence analysis of peptides derived from trypsin and Staphylococcus proteinase digestion of the protein. The molecule consisted of 104 amino acids and had an amino terminus that was blocked by pyrrolidonecarboxylic acid. Heterogeneity was not observed at any residue, which suggests that the material sequenced consisted of a single serum amyloid A species. The protein is highly homologous to serum amyloid A from humans and other animals, particularly in the middle portion of the molecule (positions 33 to 63), which suggests that this region may be important in its function. This highly conserved region may also contain the determinants for amyloid formation.
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PMID:The primary structure of serum amyloid A protein in the rabbit: comparison with serum amyloid A proteins in other species. 174 6

Interleukin 6 (IL6) is the new definition of a group of cytokines previously named according to their biological activity, e.g. B cell stimulatory factor 2 (BSF-2), hybridoma plasmocytoma-growth factor (HGF), interferon-beta 2 (IFN-beta 2), hepatocyte stimulating factor (HSF). It has recently been suggested that IL6 may represent the major mediator of acute-phase protein response whereas IL1 beta and TNF-alpha could play a minor role. We compared the effect of the three cytokines on hepatic protein synthesis by performing in vitro as well as in vivo experiments. Human hepatoma cells (PLC/PRF5) were exposed to each cytokine separately for 20 h, and the effect was then studied at the protein and RNA level. All three cytokines reduced albumin and increased C3 and ceruloplasmin biosynthesis. The cytokines induced the same effect at the RNA level indicating that the modulation was pretranslational. The effect of the cytokines was specific since actin gene expression was not changed; furthermore the effect was blocked by specific antibodies against the cytokines. The effect of the single cytokines was dose and time dependent, and quantitatively comparable. None of the cytokines was able to alter alpha 1-anti-trypsin synthesis. In vivo experiments with mice showed that IL1 beta and TNF-alpha both induce serum amyloid A (SAA) mRNA in the mouse liver and increase factor B (Bf) gene expression. Human recombinant IL6 induced SAA gene expression and it also had a weak positive effect on Bf gene expression after i.p. injection. These data demonstrate that the three cytokines studied are quantitatively and qualitatively comparable, and that all three are probably involved in acute-phase protein response.
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PMID:Interleukin 6, the third mediator of acute-phase reaction, modulates hepatic protein synthesis in human and mouse. Comparison with interleukin 1 beta and tumor necrosis factor-alpha. 313 37

The amino acid sequence of serum amyloid A (SAA) protein from mink was established by characterization of peptides derived from digestion of the protein with trypsin and from cleavage with BNPS-skatole. In three positions, two amino acid residues were found, showing that the protein is polymorphic. In position 10 both valine and isoleucine were found, while only valine was observed in protein AA. Prominent sequence homologies with protein SAA and protein AA from other species were seen, particularly corresponding to the segment between positions 31 and 54, but also in the C-terminal part of protein SAA, which is not shared by protein AA.
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PMID:The amino acid sequence of serum amyloid A (SAA) protein in mink. 342 42

Secondary amyloidosis was induced in CBA/J mice by subcutaneous injections of azocasein after priming with amyloid-enhancing factor. Amyloid fibrils were isolated from spleens and the subunit amyloid A (AA) protein purified by gel filtration on a column of Sepharose CL6B. The AA protein was fragmented with trypsin, cyanogen bromide, and Staphylococcus protease, and the peptides were purified by reverse-phase high-performance liquid chromatography. This protein is composed of 73 amino acid residues arranged in a single polypeptide chain with homogeneous amino and carboxyl terminals. Sequence homology with protein AA from other species is quite high with near identity for residues 31 through 54. This sequence is identical to the partial structures for CBA/J mouse AA and serum amyloid A (SAA) previously reported. It is also an exact match to a predicted 73-residue segment from one form of mouse SAA complementary DNA.
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PMID:Primary structure of amyloid fibril protein AA in azocasein-induced amyloidosis of CBA/J mice. 361 54

Erythrocyte sedimentation rate is normal in 20% to 25% of patients with discitis due to common pathogens. We evaluated serum amyloid A (SAA) protein and urinary trypsin inhibitory activity in osteoarticular infections comparatively with erythrocyte sedimentation rate and serum C-reactive protein in 20 patients including 14 with discitis due to common pathogens and 6 with septic arthritis. Assays were performed on D0, D8, D15, D30, and D60 after initiation of antimicrobial therapy. On D0, all four markers were significantly higher in patients with septic arthritis than in patients with discitis. C-reactive protein levels exhibited the fastest kinetics with a return to normal values within 15 days in both conditions. Urinary trypsin inhibitory activity was only slightly elevated in patients with discitis and returned to normal within 30 days in both conditions. Serum amyloid A levels required 30 to 60 days to return to normal. Erythrocyte sedimentation rate exhibited the slowest kinetics, with normal values being achieved only after 60 days. Although simple, rapid, and inexpensive, urinary trypsin inhibitory activity determination exhibits poor sensitivity. Serum amyloid A assay is not routinely available but may be a valuable parameter for monitoring patients whose erythrocyte sedimentation rate and C-reactive protein level are normal (as in 2 of our patients with discitis).
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PMID:[Value of the assay of protein SAA and urinary antitrypsin activity in osteoarticular infections]. 805 24

We show that murine macrophages that have ingested cell membranes as a source of cholesterol exhibit a marked increase in acyl-CoA:cholesterol acyl transferase (ACAT) activity. Exposure of these macrophages to acute-phase high-density lipoprotein (HDL) results in a marked reduction of ACAT and enhancement of cholesteryl ester hydrolase (CEH) activities, phenomena not seen with native HDL. These complementary but opposite effects of acute-phase HDL on the two enzyme systems that regulate the balance between esterified (storage) cholesterol and unesterified (transportable) cholesterol are shown to reside with serum amyloid A (SAA) 2.1, an acute-phase apolipoprotein of HDL whose plasma concentration increases 500- to 1,000-fold within 24 h of acute tissue injury. Mild trypsin treatment of acute-phase HDL almost completely abolishes the apolipoprotein-mediated effects on the cholesteryl ester cycle in cholesterol-laden macrophages. The physiological effect of SAA2.1 on macrophage cholesterol is to shift it into a transportable state enhancing its rate of export, which we confirm in tissue culture and in vivo. The export process is shown to be coupled to the ATP binding cassette transport system. Our findings integrate previous isolated observations about SAA into the sphere of cholesterol transport, establish a function for a major acute-phase protein, and offer a novel approach to mobilizing macrophage cholesterol at sites of atherogenesis.
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PMID:Promoting export of macrophage cholesterol: the physiological role of a major acute-phase protein, serum amyloid A 2.1. 1223 72

Immunodepletion of albumin to improve the 2-D gel resolution of human plasma proteins has recently been described. With the importance of mouse models in many studies in which serum or plasma is often analyzed, we have adopted this approach to immunoprecipitate mouse albumin and evaluated its effectiveness for 2-D separation of mouse plasma proteins. Purified polyclonal antibodies against mouse albumin were effective depleting intact albumin as well as its numerous fragments from mouse plasma samples. Removal of albumin resulted in better resolution of mouse plasma proteins. Three proteins, alpha2-macroglobulin, coagulation factor XII, and hemopexin, that were previously either undetectable or poorly resolved, were identified from albumin-depleted 2-D gels by peptide mass fingerprinting. Albumin depletion also led to partial loss of several other proteins such as clusterin and gelsolin. This loss can be attributed to the interaction with albumin itself because the specificity of the antibody was demonstrated by Western blot. When applying this method to the 2-D separation of plasma from inflamed mouse induced by cutaneous burn injury with superimposed Pseudomonas aeruginosa infection, the upregulation of inter alpha-trypsin inhibitor heavy chain 4 (ITIH4) and hemopexin was unambiguously detected along with other mouse acute-phase proteins (APP), including haptoglobin and serum amyloid A. Based on the significant increase of ITIH4, we propose that this protein is a new member of mouse APP that are upregulated during the inflammatory response.
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PMID:Immunodepletion of albumin for two-dimensional gel detection of new mouse acute-phase protein and other plasma proteins. 1613 Jan 72

SJL mice colonized with RcsX lymphoma cells undergo a rapid inflammatory response associated with biological and physiological effects including increased nitric oxide production and mutations in spleen DNA. By 2 weeks postcolonization, these changes were accompanied by both up- and down-regulation of a number of plasma proteins. In the experiments reported here, plasma from individual SJL mice was analyzed at several time-points over the 2-week period to determine if there were sets of proteins whose expression varied in concert and thus might serve as early biomarkers for inflammation-related disorders. Samples were collected just prior to injection of the RcsX cells and then after 4, 8, and 12 days. Albumin and immunoglobulins were depleted, and the samples were resolved by 1D gel electrophoresis. The gels were cut into 20 slices, and the proteins were digested in-gel with trypsin. The digests were treated with iTRAQ reagents and then analyzed using LC/MS/MS. The resulting data were processed with two software packages, that is, ProQuant and Spectrum Mill, and then subjected to K-means cluster analysis (K = 4). The four clusters revealed a set of highly up-regulated proteins, a set of progressively up-regulated proteins, a set with no major changes, and a set that declined. The first cluster included haptoglobin and serum amyloid A; the second included groups with several functions including protease inhibition, cell motility, and transport. The iTRAQ results for a selection of the up-regulated proteins, including haptoglobin, hemopexin, serum amyloid P component, and ceruloplasmin, were confirmed with Western blots. Prominent down-regulated proteins included esterase-1, paraoxonase, and alpha-2-macroglobulin. Approximately 50% of the up-regulated proteins are canonical acute phase proteins, while the remainder are regulated by the Nrf2 transcription factor.
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PMID:Comparative time-dependent analysis of potential inflammation biomarkers in lymphoma-bearing SJL mice. 1738 19

Time-course changes in the concentration of serum amyloid A (SAA), a major acute phase protein, were measured in a cat with pancreatitis over an 831-day period and compared with changes in WBC count and feline trypsin-like immunoreactivity (fTLI). SAA concentration was increased at the onset of the disease and gradually decreased over 5 days of treatment with an improvement in the clinical condition. In contrast, fTLI concentration and WBC count were not increased at the onset of the disease but increased gradually during the 5 days of treatment. Long-term monitoring from days 68 to 831 revealed a good correlation between SAA concentration and the reoccurrence of clinical signs in the cat; however, WBC count did not increase even with the exacerbation of disease. These findings suggest that the SAA concentration may be a useful marker for evaluating response to treatment and disease exacerbation in feline pancreatitis.
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PMID:Time-course monitoring of serum amyloid A in a cat with pancreatitis. 1922 63

Cord blood transplantation (CBT) is frequently associated with pre-engraftment immune reaction (PIR), which is characterized by high-grade fever that peaks around day 9 of transplantation. PIR mimics hyperacute GVHD or engraftment syndrome; however, it is considered to be of different etiology as it occurs before engraftment. Proteomic patterns have been studied in the fields of transplantation, but no specific marker has been identified. As there are no data to confirm the mechanism of PIR, we used a surface-enhanced laser desorption/ionization time-of-flight mass spectroscopy (SELDI-TOF MS) system to identify a specific marker for PIR. The protein expression profile of serum samples from CBT patients was analyzed with a SELDI-TOF MS system. A protein peak that commonly predominated in PIR was purified by an anion exchange column, isolated by SDS-PAGE, and identified by in-gel trypsin digestion, and mass fingerprinting. A 8.6-kDa protein and 11-kDa protein that increased by 10- to 100-fold in the serum of patients during PIR was identified as anaphylatoxin C4a and serum amyloid A. SELDI-TOF MS system in combination with other proteomic methods could serve as a potential diagnostic tool in discovering biomarkers for PIR after CBT.
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PMID:Identification of molecular markers for pre-engraftment immune reactions after cord blood transplantation by SELDI-TOF MS. 2022 53


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