scholarly journals Primary structure of the A chain of human complement-classical-pathway enzyme C1r. N-terminal sequences and alignment of autolytic fragments and CNBr-cleavage peptides

1985 ◽  
Vol 225 (1) ◽  
pp. 135-142 ◽  
Author(s):  
J Gagnon ◽  
G J Arlaud
Keyword(s):  
Serine Proteinase ◽  
Complete Sequence ◽  
Classical Pathway ◽  
Human Complement ◽  
Chain Fragment ◽  
Single Polypeptide Chain ◽  
Tryptic Cleavage ◽  
Cnbr Cleavage ◽  
Single Polypeptide ◽  
A Chain

Activated human complement-classical-pathway enzyme C1r has previously been shown to undergo autolytic cleavages occurring in the A chain [Arlaud, Villiers, Chesne & Colomb (1980) Biochim. Biophys. Acta 616, 116-129]. Chemical analysis of the autolytic products confirms that the A chain undergoes two major cleavages, generating three fragments, which have now been isolated and characterized. The N-terminal alpha fragment (approx. 210 residues long) has a blocked N-terminus, as does the whole A chain, whereas N-terminal sequences of fragments beta and gamma (approx. 66 and 176 residues long respectively) do not, and their N-terminal sequences were determined. Fragments alpha, beta and gamma, which are not interconnected by disulphide bridges, are located in this order within C1r A chain. Fragment gamma is disulphide-linked to the B chain of C1r, which is C-terminal in the single polypeptide chain of precursor C1r. CNBr cleavage of C1r A chain yields seven major peptides, CN1b, CN4a, CN2a, CN1a, CN3, CN4b and CN2b, which were positioned in that order, on the basis of N-terminal sequences of the methionine-containing peptides generated from tryptic cleavage of the succinylated (3-carboxypropionylated) C1r A chain. About 60% of the sequence of C1r A chain (440-460 residues long) was determined, including the complete sequence of the C-terminal 95 residues. This region shows homology with the corresponding parts of plasminogen and chymotrypsinogen and, more surprisingly, with the alpha 1 chain of human haptoglobin 1-1, a serine proteinase homologue.

scholarly journals A novel proteinase from human pancreas

1984 ◽  
Vol 219 (3) ◽  
pp. 735-742 ◽  
Author(s):  
A Sziegoleit
Keyword(s):  
Binding Protein ◽  
Sodium Dodecyl ◽  
Serine Proteinase ◽  
Human Pancreas ◽  
Single Polypeptide Chain ◽  
Quantitative Measurements ◽  
Alpha 1 Antitrypsin ◽  
Single Polypeptide ◽  
Nitrophenyl Ester ◽  
Cholesterol Binding

A cholesterol-binding protein was previously isolated from human pancreas [Sziegoleit (1982) Biochem. J. 207, 573-582] and shown to consist of a single polypeptide chain with an apparent Mr of 28 000 and an isoelectric point of pH 4.9. In further investigations, a proteolytic activity was observed to be present in preparations of this protein. The enzyme activity was not dissociable from the cholesterol-binding protein. It decreased in the presence of sodium dodecyl sulphate or urea parallel to degradation of the protein, indicating autodegradation in the presence of these denaturants. Glucagon digestion studies indicated the carbonyl bond of alanine to be a favoured site of the enzymic cleavage. The proteinase was inactive against chromogenic substrates relatively specific for elastase, trypsin and chymotrypsin, but was found to cleave benzyloxycarbonylalanine p-nitrophenyl ester efficiently. The enzyme was inactivated by phenylmethanesulphonyl fluoride and was thus classified as a serine proteinase. Autoradiographic studies demonstrated binding to serum alpha 1-antitrypsin and alpha 2-macroglobulin in a similar manner to that observed with other pancreatic endo-proteinases. The collective results indicate that the isolated protein, provisionally named ‘cholesterol-binding pancreatic proteinase’, is a novel proteinase of the human pancreas. Quantitative measurements indicate that it comprises 4-6% of total protein in pancreatic secretions.

scholarly journals The amino acid sequence of ferredoxin from Triticum aestivum (wheat)

1979 ◽  
Vol 179 (2) ◽  
pp. 373-378 ◽  
Author(s):  
I Takruri ◽  
D Boulter
Keyword(s):  
Triticum Aestivum ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Polypeptide Chain ◽  
Plant Type ◽  
Considerable Similarity ◽  
Single Polypeptide Chain ◽  
N Terminus ◽  
Cnbr Cleavage ◽  
Single Polypeptide

The amino acid sequence of the ferredoxin of Triticum aestivum (wheat) was determined by using a Beckman 890C sequencer in combination with the dansyl–phenylisothiocyanate method to characterize peptides obtained by tryptic, chymotryptic and thermolytic digestion of CNBr-cleavage fragments. The molecule consists of a single polypeptide chain of 97 residues and has an unblocked N-terminus. It shows considerable similarity to other plant-type ferredoxins.

scholarly journals The purification and properties of the second component of guinea-pig complement

1982 ◽  
Vol 205 (1) ◽  
pp. 59-67 ◽  
Author(s):  
M A Kerr ◽  
J Gagnon
Keyword(s):  
Amino Acid ◽  
Guinea Pig ◽  
Sequence Homology ◽  
Polypeptide Chain ◽  
Classical Pathway ◽  
Factor B ◽  
Single Polypeptide Chain ◽  
Purification And Properties ◽  
Rate Of Decay ◽  
Single Polypeptide

A method has been developed for the purification to homogeneity of guinea-pig complement component C2. Contrary to previous reports, guinea-pig C2 is a single polypeptide chain with apparent mol.wt. of 102000, the same as human C2. It is cleaved by C1s to yield fragments C2a (apparent molwt. 74000) and C2b (apparent mol.wt. 34000). The amino acid composition and N-terminal sequences of these fragments are similar to those of human C2a and C2b. Human and guinea-pig C2 show more extensive sequence homology to Factor B than previously identified. The known homology around the sites of cleavage by C1s and Factor D has now been extended by a stretch of ten identical or conservatively substituted residues. Sequence homology has now been identified at the N-terminal of C2b and Factor Ba. The properties of the classical-pathway C3 convertases assembled from human C4b, C1s and human or guinea-pig C2 have been compared. The rates of cleavage of human and guinea-pig C2 by C1s (and therefore the rates of assembly of the C3 convertases) are similar. The rate of decay of the activity of the C3 convertase formed from guinea-pig C2 is 10-fold lower than for human C2. This greater stability reflects a higher affinity of guinea-pig C2a for human C4b. The presence of C2b is not necessary for C3 convertase activity.

scholarly journals A 33 kDa serine proteinase from Scedosporium apiospermum

1996 ◽  
Vol 315 (1) ◽  
pp. 119-126 ◽  
Author(s):  
Gérald LARCHER ◽  
Bernard CIMON ◽  
Franç;oise SYMOENS ◽  
Guy TRONCHIN ◽  
Dominique CHABASSE ◽  
...  
Keyword(s):  
Carbon Sources ◽  
Gel Filtration ◽  
Serine Proteinase ◽  
Biochemical Properties ◽  
Enzyme Synthesis ◽  
Scedosporium Apiospermum ◽  
Human Fibrinogen ◽  
Single Polypeptide Chain ◽  
Single Polypeptide

An extracellular proteinase produced by the filamentous fungus Scedosporium apiospermum has been purified and characterized. Initially, in vitro conditions for enzyme synthesis were investigated. The highest yield of enzyme production was obtained when the fungus was cultivated in modified Czapek–Dox liquid medium supplemented with 0.1% bacteriological peptone and 1% (w/v) glucose as the nitrogen and carbon sources respectively. Purification to homogeneity of the proteinase was accomplished by (NH4)2SO4 precipitation, followed by gel filtration through Sephadex G-75 and finally affinity chromatography through immobilized phenylalanine. Analysis of the purified enzyme by SDS/PAGE revealed a single polypeptide chain with an apparent molecular mass of 33 kDa. Further investigation of its physical and biochemical properties disclosed numerous similarities with those of the previously described serine proteinase of Aspergillus fumigatus. The enzyme was not glycosylated and its pI was 9.3. Proteinase activity was optimum between 37 and 50 °C and at pH 9.0, but remained high within a large range of pH values between 7 and 11. The inhibition profile and N-terminal amino acid sequencing confirmed that this enzyme belongs to the subtilisin family of serine proteinases. In agreement with this, the specific synthetic substrate N-succinyl-Ala-Ala-Pro-Phe-p-nitroanilide proved to be an excellent substrate for the proteinase, with an estimated Km of 0.35 mM. Like the alkaline proteinase of A. fumigatus, this enzyme was able to degrade human fibrinogen, and thus may act as a mediator of the severe chronic bronchopulmonary inflammation from which cystic fibrosis patients suffer.

C1r serine proteinase of human complement: A case of intramolecular autolytic activation

1985 ◽  
Vol 5 (10-11) ◽  
pp. 831-837 ◽  
Author(s):  
Gérard J. Arlaud ◽  
Maurice G. Colomb ◽  
Christian L. Villiers
Keyword(s):  
Domain Structure ◽  
Serine Proteinase ◽  
Basic Mechanism ◽  
Short Review ◽  
Structure And Function ◽  
Activation Mechanism ◽  
Classical Pathway ◽  
Human Complement ◽  
And Function

This paper presents a short review of our contribution to the knowledge of the structure and function of human Clr, the activation unit of C1, the first component of the classical pathway of complement. On the basis of the domain structure of Clr, a model accounting for its autolytic activation mechanism is proposed. We suggest that this represents the basic mechanism of C1 function.

scholarly journals The Crystal Structure of C2a, the Catalytic Fragment of Classical Pathway C3 and C5 Convertase of Human Complement

2007 ◽  
Vol 367 (1) ◽  
pp. 224-233 ◽  
Author(s):  
Vengadesan Krishnan ◽  
Yuanyuan Xu ◽  
Kevin Macon ◽  
John E. Volanakis ◽  
Sthanam V.L. Narayana
Keyword(s):  
Crystal Structure ◽  
Classical Pathway ◽  
Human Complement ◽  
Catalytic Fragment

Debranching enzyme from rabbit skeletal muscle; Evidence for the location of two active centres on a single polypeptide chain

FEBS Letters ◽  
1975 ◽  
Vol 58 (1-2) ◽  
pp. 181-185 ◽  
Author(s):  
Edna J. Bates ◽  
Gillian M. Heaton ◽  
Carol Taylor ◽  
John C. Kernohan ◽  
Philip Cohen
Keyword(s):  
Skeletal Muscle ◽  
Polypeptide Chain ◽  
Rabbit Skeletal Muscle ◽  
Debranching Enzyme ◽  
Single Polypeptide Chain ◽  
Single Polypeptide ◽  
Active Centres

N-Terminal amino acid sequence of rat tonin: homology with serine proteases

1978 ◽  
Vol 56 (9) ◽  
pp. 920-925 ◽  
Author(s):  
N. G. Seidah ◽  
R. Routhier ◽  
M. Caron ◽  
M. Chrétien ◽  
S. Demassieux ◽  
...  
Keyword(s):  
Serine Proteases ◽  
Terminal Sequence ◽  
Renin Substrate ◽  
Amino Terminal ◽  
Single Polypeptide Chain ◽  
Serine Protease Family ◽  
Terminal Amino ◽  
Single Polypeptide ◽  
Carboxy Terminal ◽  
Amino Terminal Sequence

In this paper, we present the amino-terminal sequence of rat tonin, an endopeptidase responsible for the conversion of angiotensinogen, the tetradecapeptide renin substrate, or angiotensin I to angiotensin II. It is shown that isoleucine and proline occupy the amino- and carboxy-terminal residues respectively. The N-terminal sequence analysis permitted the identification of 34 out of the first 40 residue s of the single polypeptide chain composed of 272 amino acids. The se results showed an extensive homology with the sequence of many serine proteases of the trypsin–chymotrypsin family. This information, coupled with the slow inhibition of tonin by diisopropylfluorophosphate, classified this enzyme as a selective endopeptidase of the active serine protease family.

scholarly journals Hepatic microsomal epoxide hydrase. Chemical evidence for a single polypeptide chain.

1979 ◽  
Vol 254 (14) ◽  
pp. 6240-6243 ◽  
Author(s):  
G C DuBois ◽  
E Appella ◽  
R Armstrong ◽  
W Levin ◽  
A Y Lu ◽  
...  
Keyword(s):  
Polypeptide Chain ◽  
Single Polypeptide Chain ◽  
Single Polypeptide ◽  
Chemical Evidence
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