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

Amyloid deposits in several heredofamilial forms of amyloidosis are chemically related to transthyretin (TTR, the protein usually referred to as prealbumin). A genetically abnormal TTR may be involved. Studies were conducted on TTR isolated from sera of patients with familial amyloidotic polyneuropathy (FAP), and on amyloid fibril protein (AFp) isolated from tissues of two Portuguese patients who died with FAP. AFp, purified by affinity chromatography on retinol-binding protein (RBP), resembled plasma TTR in forming a stable tetrameric structure, and in its binding affinities for both thyroxine and RBP. Purified AFp was found to comprise a TTR variant with a methionine for valine substitution at position 30. This conclusion was based upon studies that included: (i) comparative peptide mapping by reverse-phase high-performance liquid chromatography after trypsin digestion; (ii) cyanogen bromide (CNBr) cleavage studies; and (iii) amino acid microsequence analysis of selected tryptic and CNBr peptides. The variant TTR was also found to be present in serum samples from FAP patients, along with larger amounts of normal TTR. An effective, small-scale procedure was developed to determine whether or not the variant TTR was present in the plasma of an individual subject. This procedure involved isolation of TTR by affinity chromatography on RBP, followed by CNBr cleavage, and analysis for the presence of specific aberrant CNBr peptides. Studies with six kindreds, including 21 asymptomatic children of 6 patients with FAP, showed that the "abnormal" TTR can be detected and used as a preclinical marker of the disease in affected children of patients with FAP. It is likely that the variant TTR represents a point mutation within the TTR structural gene, and that the normal and mutant genes act as co-dominant alleles at a single locus in FAP. The distribution of the mutant TTR within the six families was consistent with the autosomal dominant mode of inheritance of FAP. The mutant TTR apparently selectively deposits in tissues as the amyloid characteristic of the disease.
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PMID:Family studies of the genetic abnormality in transthyretin (prealbumin) in Portuguese patients with familial amyloidotic polyneuropathy. 609 6

Color-coded computer graphics representations of the electrostatic potentials of trypsin, trypsin-inhibitor, prealbumin and its thyroxine complex, fragments of double-helical DNA, and a netropsin--DNA complex illustrate the electrostatic and topographic complementarity in macromolecule-ligand interactions. This approach is powerful in revealing intermolecular specificity and shows promise of having predictive value in drug design.
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PMID:Electrostatic potential molecular surfaces. 628 64

Amyloid fibril protein with a molecular weight of 8K daltons, in addition to one of 16K daltons, has been isolated and characterized from an autopsy sample of a patient with familial amyloid polyneuropathy in a Japanese family from Ogawa Village, Nagano Prefecture. The component was shown to react with an antiserum to normal plasma prealbumin, as did the other. Following the purification by reverse phase liquid chromatography, it was digested with trypsin and the peptides, after the purification by HPLC were sequenced. The data showed that the component was a distinct fragment whose sequence was identical with that of the residues from Gly-6 to Tyr-78 of the prealbumin, except that it had a methionine for a valine at position 25. This corresponded with the position 30 where a valine residues has been reported for the sequence of the normal plasma prealbumin.
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PMID:A variant prealbumin-related low molecular weight amyloid fibril protein in familial amyloid polyneuropathy of Japanese origin. 651 15

Prealbumin from an individual with heredofamilial amyloid polyneuropathy of Swedish origin was isolated from plasma by using a three-step procedure involving ion exchange, Affi-gel Blue affinity chromatography, and gel filtration. This prealbumin and its associated amyloid fibril subunit protein were digested with trypsin and the resulting peptides were separated by high performance liquid chromatography. Comparison with normal prealbumin peptides showed that an amino acid substitution of a methionine for a valine had occurred at position 30. In the plasma prealbumin, the abnormal residue accounted for 1/3rd of the material while in the amyloid fibrils it accounted for 2/3rds. From this sequence information and the known three-dimensional structure of the prealbumin molecule, a mechanism for the amyloid formation is proposed. It involves formation of the amyloid fibrils by addition of prealbumin dimers or tetramers to the aggregate. Each dimer must contain at least one variant peptide chain while the tetramer must contain at least two abnormal chains. Either of these models can account for the observed amount of normal prealbumin in amyloid fibrils. No proteolytic processing of this molecule is required because the entire undegraded prealbumin molecule is found in the fibrils.
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PMID:Primary structure of an amyloid prealbumin and its plasma precursor in a heredofamilial polyneuropathy of Swedish origin. 658 72

Amyloid fibril protein in patients with familial amyloidotic polyneuropathy is known to be chemically related to transthyretin (TTR), the plasma protein that is usually referred to as prealbumin. A genetically abnormal TTR may be involved in this disease. Studies were conducted on amyloid fibril protein (AFp) isolated from tissues of two Portuguese patients who died with familial amyloidosis, and on TTR isolated from sera of patients with this disease. AFp, purified by affinity chromatography on retinol-binding protein linked to Sepharose, resembled plasma TTR in forming a stable tetrameric structure, and in its binding affinities for both thyroxine and retinol-binding protein. The structural studies included: (a) comparative peptide mappings by reverse-phase high performance liquid chromatography (HPLC) after trypsin digestion; (b) cyanogen bromide cleavage studies; and (c) amino acid microsequence analysis of selected tryptic and CNBr peptides. On the basis of the known amino acid sequence of TTR, comparative tryptic peptide maps showed the presence of a single aberrant tryptic peptide (peptide 4, residues 22-34) in AFp as compared with TTR. This aberrant peptide contained a methionine residue, not present in normal tryptic peptide 4. CNBr cleavage of AFp produced two extra peptide fragments, which were demonstrated, respectively, by HPLC analysis and by sodium dodecyl sulfate-gel electrophoresis. Sequence analyses indicated the presence of a methionine-for-valine substitution at position 30 in AFp as compared with TTR. Thus, the purified amyloid fibril protein comprised a TTR variant with a methionine-forvaline substitution at position 30. A single nucleotide change in a possible codon for valine 30 could explain the substitution. The variant TTR was also present in the TTR isolated from the pooled sera of amyloidoses patients, together with larger (four- to six-fold) amounts of the normal TTR. Thus, in these patients, the variant TTR was circulating in plasma, along with larger amounts of normal TTR. We suggest that the variant TTR represents the specific biochemical cause of the disease, and that this abnormal form of TTR selectively deposits in tissues as the amyloid characteristic of the disease.
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PMID:Amyloid fibril protein in familial amyloidotic polyneuropathy, Portuguese type. Definition of molecular abnormality in transthyretin (prealbumin). 673 44

Two forms of urinary trypsin inhibitor, A and B, were purified from the urine of pregnant women. Form A was the only inhibitor present in fresh urine and inhibitor B arose from degradation of A upon storage of urine. The molecular masses of A and B were about 44 and 20 kDa, respectively, as judged from dodecyl-sulfate polyacrylamide gel electrophoresis, but about 60 kDa and 30 kDa, respectively, as judged from gel filtration analysis. The discrepancy can perhaps be explained by the carbohydrate content amounting to about 10% of each inhibitor. After reduction with mercaptoethanol, inhibitor A and inhibitor B had identical apparent molecular masses of about 20 kDa on dodecyl-sulfate gel electrophoresis. These results and the results of amino acid analysis suggest that one molecule of inhibitor A yields two molecules of inhibitor B. On agarose gel electrophoresis inhibitor A migrated as a rather broad band in the prealbumin region and inhibitor B as 3 well defined bands in the beta-region. Specific antisera were raised against inhibitor A and B. The two inhibitors showed the immunologic reaction of identity with each other and with the plasma inter-alpha-trypsin inhibitor, when using either antiserum. The inhibitors both gave quantitative inhibition of bovine trypsin, the results indicating a 4/1 trypsin/inhibitor molar ratio for A and a 2/1 ratio for B. The two substances also effectively inhibited granulocyte elastase. No inhibition of porcine pancreatic elastase was demonstrable.
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PMID:Human granulocyte elastase is inhibited by the urinary trypsin inhibitor. 692 41

Pig serum proteins were analysed by horizontal polyacrylamide gel electrophoresis, with a discontinuous buffer system (pH 9.0). A 12% acrylamide concentration in the separation gel was used. Each of the two paralbumin (Pa) alleles gave rise to two closely migrating fractions. The polymorphic Pa was identified as an alpha1-protease inhibitor as the Pa fractions inhibited the esterolytic activity of both bovine trypsin and chymotrypsin. Therefore, it has been proposed that the locus symbol for this prealbumin be changed to Pi-1. The protease inhibitory spectra and electrophoretic mobility of the Pa (Pi-1) fractions suggested that this protein was probably the same as the pig serum alpha1-protease inhibitor described in some earlier studies and that it corresponds to human serum alpha 1-protease inhibitor (Pi).
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PMID:Polymorphic serum prealbumin (Pa) of pig, identified as and alpha1-protease inhibitor. 697 15


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