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)

Serine protease inhibitors in extracts from three North American leeches, Nephelopsis obscura, Erpobdella punctata and Hemopis marmorata have been separated by anion exchange chromatography and the activity pattern against human granulocyte elastase and porcine chymotrypsin and trypsin determined. All three leech species contained a major peak with anti-trypsin activity, but Hemopis was unique in that the trypsin inhibitor was equally active against chymotrypsin. Nephelopsis was rich in anti-elastase activity of two types, one which was also active against chymotrypsin, and one which was a specific elastase inhibitor. Erpobdella contained inhibitors against elastase and chymotrypsin but with major activity against the latter.
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PMID:Serine protease inhibitors of North American leeches. 348 11

Inhibitors, of trypsin, plasmin, alpha-chymotrypsin and granulocyte elastase were demonstrated in salivary gland extracts from two species of leeches. Haementeria ghilianii and Haementeria officinalis. Preliminary fractionation of salivary gland extracts from Haementeria ghilianii allowed separation of protease inhibitors from hementin a fibrinogenolytic blood anticoagulant. It was found that the anticoagulant activity resided only in hementin-containing fractions and did not parallel protease inhibitory activity.
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PMID:Protease inhibitors in Haementeria leech species. 623 28

Hirudin from whole leeches behaves like hirudin from leech heads and "pseudohirudin" from leech bodies during isolation and purification by means of acetone and ethanol fractionation, affinity chromatography on trypsin-Sepharose, and isoelectric focusing. However, the antithrombin activity of the hirudin fractions obtained after isoelectric focusing was approximately three times lower than that of the corresponding hirudin fractions from the heads. The "pseudohirudin" fractions had practically no antithrombin activity. In hirudin from whole leeches isoleucine and valine were identified as the N-terminal amino acid. Isoleucine was identified as the dominant amino acid in hirudin from leech heads. The dominant N-terminal amino acid in "pseudohirudin" from leech bodies was valine. The data on antithrombin activity and N-terminal amino acids indicate that hirudin from whole leeches contains admixtures of inactive "pseudohirudin". In contrast to hirudin from leech heads, "pseudohirudin" represents associates of di- and three-isomers. The molecular weight of the "pseudohirudin" molecule is 2000 lower than the molecular weight of hirudin, which corresponds to a difference of 20 amino acid residues, calculated from the total number of amino acid residues in the preparations.
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PMID:Hirudin from leech heads and whole leeches and "pseudo-hirudin" from leech bodies. 661 79

During isolation and purification involving fractionation by acetone, ethanol and affinity chromatography on trypsin-Sepharose and isoelectrofocusing hirudin from whole leeches behaves as the inhibitor isolated from leech heads and "pseudohirudin" from leech bodies. The antithrombin activity of hirudin fractions obtained by isoelectrofocusing is about three times less than that of the corresponding hirudin fractions from the heads. The "pseudohirudin" fractions are practically devoid of the antithrombin activity. In hirudin prepared from whole leeches isoleucine and valine were identified as N-terminal amino acids. The antithrombin activity and N-terminal amino acids suggest that hirudin from whole leeches contains admixtures of inactive "pseudohirudin". Hirudin from leech heads purified by complexing with thrombin possesses the activity of 15600 ATNIH units per pg of protein and has isoleucine as an N-terminal amino acid.
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PMID:[Comparative properties of hirudin from whole leeches and from leech heads and bodies]. 738 67

Antistasin, a potent inhibitor of the blood coagulation factor Xa, is the prototype of a novel family of serine-proteinase inhibitors. We have now isolated, sequenced and characterized an antistasin-type inhibitor from the medical leech Hirudo medicinalis. Hirustasin (Hirudo antistasin) was purified to apparent homogeneity by cation-exchange and affinity chromatography. Amino acid sequencing of the 55 amino acid protein (M(r) 5866) revealed that hirustasin is the only antistasin-type protein known to consist of one domain only; 27% and 32% sequence identity was found to the first and second domains of antistasin, respectively, and a nearly exact conservation of the spacing of the ten cysteine residues. Hirustasin is the first inhibitor of tissue kallikrein identified in leeches, and is also a tight-binding inhibitor of trypsin, chymotrypsin and neutrophil cathepsin G. However, despite the high similarity to antistasin, particularly in the vicinity of the putative reactive-site peptide bond, hirustasin neither inhibits blood coagulation in vitro nor amidolytic activity of isolated factor Xa. Thus, structural elements other than the reactive site sequence significantly influence the specificity of antistasin-type proteinase inhibitors.
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PMID:Isolation and characterization of hirustasin, an antistasin-type serine-proteinase inhibitor from the medical leech Hirudo medicinalis. 811 45

Unlike the European leech Hirudo medicinalis, the Asian jawed leech Hirudinaria manillensis is specialized for feeding on mammalian blood. In the salivary glands of both these leeches, there is a potent inhibitor of thrombin, called hirudin, which acts as an anticoagulant. We have reported previously the isolation and purification of a variant of hirudin, called bufrudin, from the head portions of Hirudinaria. In the present study, the complete amino acid sequence of bufrudin was determined by automated Edman degradation of peptide fragments generated after cleavage of protein with trypsin or thermolysin. Comparison of the primary structure of bufrudin, with hirudin HV1, show about 70% sequence identity with deletion of two amino acids, but the key amino acids at the C-terminus, involved in the inhibition of thrombin, are conserved. However, similar sequence comparison of bufrudin with hirullin P18, a hirudin variant isolated from the same leech species but from whole leech, instead of heads, reveals even less sequence identity of about 60%. From the amino acid sequence, it is suggested that the conformation of the C-terminal portion of bufrudin may be significantly different from hirullin P18, but similar to hirudin HV1, upon its interaction with thrombin. These results indicate that, as with Hirudo leech, various isoforms of hirudin also exist in Hirudinaria leech, with a significant change occurring in the structure of the molecule during the evolution of leeches.
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PMID:The complete amino acid sequence of a hirudin variant from the leech Hirudinaria manillensis. 839 94

We purified a chymotrypsin inhibitor, designated cytin, from the rhynchobdellid leech Theromyzon tessulatum. This 7.4-kDa peptide was purified to apparent homogeneity by gel-permeation and anion-exchange chromatographies, followed by reverse-phase HPLC. The structure of cytin was determined by reduction, S-beta-pyridilethylation, automated Edman degradation, and electrospray mass spectrometry. Cytin is formed by the association of two protein chains, which are linked by a disulfide bridge. Chain A consists of 43 and chain B of 22 amino acid residues. Chain B exhibits 40-63% sequence similarity with the N-terminal sequences of subtilisin/chymotrypsin inhibitors isolated from barley seeds. Cytin inhibited chymotrypsin (Ki 600 pM) and weakly inhibited trypsin (Ki 350 nM). This chymotrypsin inhibitor, in contrast to others isolated from leeches, does not inhibit elastase or cathepsin G. Furthermore, cytin (10 microM) significantly diminishes the level of human granulocyte and monocyte activation induced by lipopolysaccharide (1 U/ml) in a manner similar to that of aprotinin. These data indicate that this chymotrypsin inhibitor may be biomedically significant.
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PMID:Amino-acid-sequence determination and biological activity of cytin, a naturally occurring specific chymotrypsin inhibitor from the leech Theromyzon tessulatum. 939 20

The biochemical characterization of a serotonin (5HT) receptor and the cloning of a dopamine (DA) receptor in the central nervous system (CNS) of the leech, Theromyzon tessulatum, is presented. Additionally, DA and 5HT binding sites were examined in the CNS by Scatchard analysis which showed a single, relatively high-affinity binding site with a Kd 1.1 nM and a Bmax 126+18 fmol/mg protein for [3H]DA and a Kd 2.1 nM and a Bmax 225 fmol/mg protein for [3H]5HT. The first 88 amino acids of the 5HT receptor, isolated by a 5HT-affinity column followed by anion exchange chromatography and C3 reverse-phase HPLC exhibited a 43% sequence homology with Lymnaea stagnalis 5HT-receptor. The isolated DA receptor revealed a single protein of 45 kDa with an anti-D1-R in Western blot. The first 80 N-terminal amino acid residues and a trypsin digested fragment of 31 residues were obtained, and based on these sequencing data, a molecular biology strategy using reverse transcriptase-polymerase chain reaction, was developed. An amplified 1-kb segment was obtained. The complete deduced sequence of 416 amino acid residues exhibited about 30.6% sequence homology with the vertebrate D1 receptor family. Moreover, we further demonstrate that the leech 5HT and DA receptors also exhibit 30% sequence identity with each other, explaining their pharmacological cross-reactivity. Finally, anti-D1-R immunocytochemistry revealed positive structures in the peripheral and central nervous system, e.g., neurons, sensory fibers and immune cells. This is the first biochemical and molecular characterization of a DA receptor in leeches.
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PMID:Putative leech dopamine1-like receptor molecular characterization: sequence homologies between dopamine and serotonin leech CNS receptors explain pharmacological cross-reactivities. 968 82

We purified a new trypsin-chymotrypsin inhibitor, designated tessulin, from the rhynchobdellid leech Theromyzon tessulatum. This 9-kDa peptide was purified to apparent homogeneity by gel-permeation and anion-exchange chromatographies followed by reverse-phase HPLC. The structure of tessulin was determined by reduction, S-beta-pyridylethylation, trypsin digestion, automated Edman degradation and matrix-assisted laser desorption mass spectrometry (m/z 8985 Da). The 81-amino-acid peptide possesses 16 cysteines and exhibits a 16% sequence similarity with antistasin-type inhibitors. Tessulin inhibits trypsin (Ki 1 pM) and chymotrypsin (Ki 150 pM) and exhibits no activity with thrombin, factor Xa, cathepsin G and elastase. This is the first trypsin-chymotrypsin inhibitor isolated from leeches that does not inhibit elastase or cathepsin G, except for cytin and therin. Furthermore, tessulin, in conjunction with other serine-protease inhibitors isolated from Theromyzon (therin, theromin), significantly diminishes the level of human granulocyte and monocyte activation induced by lipopolysaccharides (10 microg). The combined level of inhibition is higher than that of aprotinin, another serine-protease inhibitor used biomedically. Thus, tessulin may be clinically significant in reducing inflammatory events.
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PMID:Amino-acid-sequence determination and biological activity of tessulin, a naturally occurring trypsin-chymotrypsin inhibitor isolated from the leech Theromyzon tessulatum. 987 32

Experimental infection of pigeon squabs and rats with encysted metacercariae from the Western Carp gudgeon (Hypseleotris klunzingeri) showed them to be infected with a new strigeid trematode, Apatemon hypseleotris. Growth and development of A. hypseleotris in pigeons were significantly higher than in rats. Eggs appeared in pigeon faeces within 7-14 days; miracidia hatched within 15-21 days and in the snail Lymnaea tomentosa released within 21 days. Cercariae experimentally encysted in the leeches Helobdella papillornata (86.7%) and Alboglossiphonia australiensis (73.3%). In fish, encystation occurred in the abdominal cavity (100%) and muscles (40%) of Hypseleotris klunzingeri, in the abdominal cavity (80%) and head (30%) of Gambusia affinis and in the abdominal cavity (62.5%) of Oncorhynchus mykiss but no encystation occurred in Moenkhausia pittieri. Freezing (-7 degrees C for 3-7 days or -21 degrees C for 8-12 hours), chilling (6 degrees C for 12 days), boiling (3 minutes) or salting for 3-5 days of encysted metacercariae did not significantly reduce infectivity. In vitro excystation of metacercariae was achieved using pepsin followed by trypsin and/or bile salts.
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PMID:Morphology and life cycle of Apatemon hypseleotris species novum from Australia including metacercariae viability and excystment. 1216 69


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