Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.24.27 (thermolysin)
 1,894 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The complete amino acid sequence of and the locations of disulfide bridges in H2-proteinase, a major non-hemorrhagic proteinase isolated from the venom of the habu Trimeresurus flavoviridis, have been determined and compared with those of HR2a, one of the hemorrhagic metalloproteinases in this venom. The strategy involved consisted of structural analysis of peptides in digests with cyanogen bromide, lysyl endopeptidase, trypsin, Staphylococcus aureus V8 protease and thermolysin. Peptides were purified by gel filtration followed by reversed-phase HPLC. H2-proteinase is a non-glycosylated single chain polypeptide consisting of 201 amino acids with an amino-terminal pyroglutamic acid, a calculated molecular weight of 22,991 and a net charge of +14 at neutral pH. There was no evidence of heterogeneity of the sequence. H2-proteinase has a typical zinc-chelating sequence and its overall sequence identity with HR2a is 73.6%. The 3 disulfide bridges in H2-proteinase link Cys-117 to Cys-196, Cys-158 to Cys-180, and Cys-160 to Cys-163, in the same manner as in the case of HR2a. In striking contrast to HR2a, it contains en extra free cysteine residue at position 94 which becomes reactive to a sulfhydryl reagent in the presence of a denaturant.
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PMID:Primary structure of H2-proteinase, a non-hemorrhagic metalloproteinase, isolated from the venom of the habu snake, Trimeresurus flavoviridis. 277 46

The occasional cleavage of the Pseudomonas cytochrome-c peroxidase (ferrocytochrome-c:hydrogen-peroxide oxidoreductase, EC 1.11.1.5) molecule into two well-defined fragments during the preparation of the enzyme is shown to be identical to that caused by elastase isolated from the culture solution of Pseudomonas aeruginosa. A cyanogen bromide fragmentation of proteolytically cleaved and of intact enzyme shows the cleaved peptide bond to be situated in cyanogen bromide fragment II. The amino-acid sequence of this fragment was established by sequencing peptides obtained with trypsin, thermolysin, chymotrypsin and o-iodosobenzoate. It is concluded from the sequence homology that the polypeptide chain of Pseudomonas peroxidase is wrapped around the high-potential heme in a similar manner as in high-potential cytochromes c in general. The specific proteolytic cleavage occurs at a Ser-Val (Leu-Pro) region which is assumed to be the site of attachment between enzyme and membrane. The cleavage of the Ser-Val bond renders the peroxidase molecule enzymatically inactive by impeding the conformational changes essential for the function of the native enzyme.
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PMID:Specific cleavage of Pseudomonas cytochrome-c peroxidase by elastase from Pseudomonas aeruginosa. 282 23

Rhodopsin in rod outer segment disk membranes was enzymatically modified by erythrocyte transglutaminase, which linked small primary amines to glutamine residues. In order to avoid formation of protein crosslinks, rhodopsin was first reductively methylated to modify its lysines. From 1.9 to 2.5 mol of putrescine, ethanolamine, or dinitrophenylcadaverine were incorporated into rhodopsin by transglutaminase during 16 h reaction time. A maximum of 3.5 mol of [14C]putrescine was incorporated per mole of rhodopsin during 48 h. Essentially all of the rhodopsin sequence containing the putrescine could be removed by limited proteolysis of the membranes by thermolysin. Glutamine residues in positions 236, 237, 238, and 344 were modified to approximately equal extents, as determined by isolation of the cyanogen bromide peptides of modified rhodopsin followed by further subdigestion of the peptides. The modified glutamine residues are located in the helix V-VI (or F1-F2) connecting loop and in the carboxyl-terminal region of rhodopsin.
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PMID:Transglutaminase modification of rhodopsin in retinal rod outer segment disk membranes. 287 89

A large-scale method for the isolation of von Willebrand factor (vWF) from human factor VIII concentrates was developed in order to study the structure of this protein and its platelet binding activity. vWF is composed of a number of glycoprotein subunits that are linked together by disulfide bonds to form a series of multimers. These multimers appear to contain an even number of subunits of 270K. Two minor components of Mr 140K and 120K were also identified, but these chains appear to result from minor proteolysis. The smallest multimer of vWF contained nearly equimolar amounts of the 270K, 140K, and 120K subunits, while the largest multimers contained less than 20% of the two minor components. Amino acid sequence analysis, amino acid composition, and cleavage by cyanogen bromide indicate that the 270K subunits are identical and each is a single polypeptide chain with an amino-terminal sequence of Ser-Leu-Ser-Cys-Arg-Pro-Pro-Met-Val-Lys and a carboxyl-terminal sequence of Glu-Cys-Lys-Cys-Ser-Pro-Arg-Lys-Cys-Ser-Lys. Platelet binding in the presence of ristocetin was 8-fold greater with multimers larger than five (i.e., containing more than 10 subunits of 270K) as compared to multimers less than three (containing less than six subunits of 270K). However, partially reduced vWF (Mr 500K), regardless of whether it was prepared from large or small molecular weight multimers, gave platelet binding similar to that of the smallest multimers. Likewise, partial proteolysis by elastase, thermolysin, trypsin, or chymotrypsin produced small "multimer-like" proteins with platelet binding properties similar to either partially reduced vWF or to the smallest multimers. We conclude that human vWF contains identical 270K subunits assembled into a multivalent structure. Disassembly by either partial reduction or partial proteolysis produces essentially monovalent protein with platelet binding properties similar to that of the smallest multimers. Multivalency is likely the primary factor responsible for the increase in biological activity with multimer size.
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PMID:Human von Willebrand factor: a multivalent protein composed of identical subunits. 301 99

The amino acid sequence of the thioredoxin isolated from the photosynthetic green sulfur bacterium Chlorobium thiosulfatophilum was determined chiefly by fast atom bombardment mass spectrometry combined with Edman degradation and tandem mass spectrometry. For this purpose, the protein was digested with trypsin, alpha-chymotrypsin, thermolysin, and Staphylococcus aureus protease or combinations thereof. Chemical cleavage with cyanogen bromide was also used alone or in combination with trypsin. The resulting sequence of 108 amino acids is as follows: Ala-Gly- Lys-Tyr-Phe-Glu-Ala-Thr-Asp-Lys-Asn-Phe-Gln- Thr-Glu-Xle-Xle-Asp-Ser-Asp-Lys-(Ala-Val)-Xle- Val-Asp-Phe-Trp-Ala-Ser-Trp-Cys-Gly-(Pro-Cys)- Met-Met-Xle-Gly-Pro-Val-Xle-Glu-Gln-Xle-Ala-Asp- Asp-Tyr-Glu-Gly-Lys-Ala-Xle-Xle-Ala-Lys-Xle-Asn- Val-Asp-Glu-Asn-Pro-Asn-Xle-Ala-Gly-Gln-Tyr-Gly- Xle-Arg-Ser-Xle-Pro-Thr-Met-Xle-Xle-Xle-Ly s- (Gly-Gly-Lys)-Val-Val-Asp-Gln-Met-Val-Gly-Ala- Xle-Pro-Lys-Asn-Met-Xle-Ala-Lys-Lys-Xle-Asp-Glu-His-Il e-Gly (where Xle represents leucine or isoleucine; sequences in parentheses are based on homology considerations). It exhibits less than 53% homology with Escherichia coli thioredoxin.
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PMID:Mass spectrometrically derived amino acid sequence of thioredoxin from Chlorobium, an evolutionarily prominent photosynthetic bacterium. 329 35

The complete amino acid sequence of Cu,Zn-superoxide dismutase (SOD) from spinach leaves has been determined on the basis of peptides obtained by cyanogen bromide (BrCN) cleavage and by enzymic hydrolyses with Achromobacter lyticus lysylendopeptidase, Staphylococcus aureus V8 protease, trypsin, and thermolysin. The spinach SOD consists of a total of 154 amino acid residues with alanine as the amino(N)-terminus and valine as the carboxy(C-)terminus. The present sequence, which has been established for the enzyme from a plant, is also highly homologous to those of the enzymes from other species. Especially, the residues essential for metal binding and enzyme activity have been extensively conserved among all of the Cu,Zn-SODs hitherto analyzed.
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PMID:Amino acid sequence of copper,zinc-superoxide dismutase from spinach leaves. 351 1

The two protamines of human sperm cell nuclei, P1 and P2, were isolated in pure form after extraction with 6M guanidine/5% mercaptoethanol and alkylation with vinyl pyridine by reversed-phase high-performance liquid chromatography. The amino-acid sequence of protamine P1 was determined by analysing the intact protein and the fragments obtained by cyanogen bromide cleavage. Out of the 50 amino-acid residues 24 are arginines and 6 are cysteines. The sequence of protamine P2 was determined by analysing the intact protein and the fragments resulting from cleavage with endoproteinase Lys-C and thermolysin. Protamine P2 was found to occur in two forms which only differ in their N-terminal regions. The form P2' is three amino-acid residues longer at the N-terminus than the form P2''. Out of the 57 amino-acid residues in the longer form 27 are arginines and 5 are cysteines. Human protamine P1 is highly homologous with the protamines isolated from bull, boar, ram and mouse sperm cells, but human protamine P2 shows a novel type of structure, although also here the dominant amino acids are arginine and cysteine.
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PMID:Isolation and amino-acid sequence analysis of human sperm protamines P1 and P2. Occurrence of two forms of protamine P2. 352 26

Riboflavin-binding protein of hen egg white (egg-white RBP) comprised 219 amino acid residues and nine disulfide bonds. To identify the locations of these bonds, the native protein was oxidized with cyanogen bromide and digested with trypsin, thermolysin, and Staphylococcus aureus V8 protease. The cystine-containing peptides were isolated by HPLC. Amino acid analyses and amino acid sequence analyses of the reduced pyridylethylated derivatives of the cystine peptides showed that seven of the disulfide bonds were as follows: Cys(24)-Cys(73), Cys(57)-Cys(138), Cys(64)-Cys(110), Cys(99)-Cys(169), Cys(116)-Cys(134), Cys(103)-Cys(152), Cys(167)-Cys(202). The other two disulfide bonds were either Cys(5)-Cys(32) and Cys(33)-Cys(77) or Cys(5)-Cys(33) and Cys(32)-Cys(77).
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PMID:Positions of disulfide bonds in riboflavin-binding protein of hen egg white. 357 Dec 3

The nicotinic acetylcholine receptor is a substrate for cAMP-dependent protein kinase both in vitro and in vivo. Recently, it has been demonstrated that phosphorylation of the nicotinic receptor by this kinase increases its rate of rapid desensitization. We now report the identification of the cAMP-dependent phosphorylation sites on the gamma and delta subunits. Two-dimensional phosphopeptide mapping of the phosphorylated gamma and delta subunits, after limit proteolysis with thermolysin, indicated that each subunit is phosphorylated on a single site. Phosphoamino acid analysis of the 32P-labeled subunits demonstrates that phosphorylation had occurred exclusively on serine residues. Purified phosphorylated subunits were cleaved with cyanogen bromide and the resultant phosphopeptides were purified by reverse-phase high performance liquid chromatography. Shorter phosphopeptides, obtained by secondary digestion with trypsin, were purified and subjected to both automated gas-phase sequencing and manual Edman degradation. The results demonstrate that the gamma subunit was phosphorylated at Ser-353, contained within the sequence Arg-Arg-Ser(P)-Ser-Phe-Ile and that the delta subunit was phosphorylated at Ser-361, contained within the sequence Arg-Ser-Ser(P)-Ser-Val-Gay-Tyr-Ser-Lys. Determination of the sites phosphorylated within the structure of the gamma and delta subunits should contribute to the molecular characterization of the regulation of desensitization of the nicotinic acetylcholine receptor by protein phosphorylation.
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PMID:Determination of the sites of cAMP-dependent phosphorylation on the nicotinic acetylcholine receptor. 368 Feb 73

Streptomyces Metallo-Proteinase Inhibitor (S-MPI) consists of 102 amino acid residues, including one methionine and two disulfide bridges. The complete amino acid sequence of S-MPI, including two disulfide bridges, was determined by sequencing of tryptic and chymotryptic peptides of two fragments obtained by cyanogen bromide cleavage followed by reduction and S-pyridylethylation of the protein. Incubation of the inhibitor with thermolysin slowly cleaved one peptide bond, Cys(64)-Val(65), which might be a reactive site of S-MPI.
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PMID:Amino acid sequence of Streptomyces metallo-proteinase inhibitor from Streptomyces nigrescens TK-23. 388 72


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