Search results for "Cyanogen Bromide"
showing 8 items of 8 documents
A new form of tumor and fetal collagen that binds laminin.
1993
Human breast and colon carcinoma tissues contain a form of collagen, not described before, composed of alpha 1 chains of similar size (approximately 100 kDa) but different charge. The three constitutive chains, separated by two-dimensional electrophoresis, are a unique acidic component, undetectable in other collagen types, with an apparent isoelectric point of 4-5, and two more basic components displaying the same electrophoretic behavior as alpha 1(III) and alpha 1(I), respectively. The acidic chain is structurally distinct from alpha 1(I) and displays a cyanogen bromide-derived fragment of similar size to CB5(III). This collagen in its native state is resistant to trypsin and metalloprot…
Partialsynthese neuer Ergolinderivate aus Clavinalkaloiden, 4. Mitt. N-1-, C-2- und N-6-monosubstituierte Agroclavine
1985
Agroclavin (1) wird in flussigem Ammoniak/Kaliumamid mit Alkyliodid am Indolstickstoff alkyliert. 1 last sich mit N-Iodsuccinimid zu 2-Iod-1 (3) umsetzen. Mit der Bromcyan-Methode wird 6-Nor-1 (4b) gewonnen und danach an N-6 alkyliert. Partial Synthesis of New Ergoline Derivatives from Clavine Alkaloids, IV: Agroclavines Monosubstituted at N-1, C-2, and N-6 Agroclavine (1) is alkylated at the indole nitrogen with alkyl iodide in ammonia/potassium amide. It is convertible to 2-iodo-1 (3) with N-iodosuccinimide. Compound 6-nor-1 can be prepared by means of the cyanogen bromide method; alkylation at N-6 is described exemplarily for the ethyl derivative.
Onco-fetal/laminin-binding collagen from colon carcinoma: detection of new sequences.
1995
We have recently identified an oncofetal-laminin binding collagen (OF/LB) composed of three alpha chains, with the apparent molecular mass of about 100 kDa each, but bearing different pI. One of the chains appears markedly acidic in a bidimensional electrophoretic system, where the NEPHGE is used as first dimension separating gel, while the two more basic chains have similar migration as alpha 1(III) and alpha 1(I) collagen chains, respectively. Sequence analyses have been performed on CNBr-peptides, derived from pepsinized triple helical molecules and on tryptic fragments obtained after in gel digestion of the acidic band. The research of sequence homology with computerized databases indic…
Primary structure and unusual carbohydrate moiety of functional unit 2-c of keyhole limpet hemocyanin (KLH)
1999
Abstract The complete amino acid sequence of the Megathura crenulata hemocyanin functional unit KLH2-c was determined by direct sequencing and matrix-assisted laser desorption ionization mass spectrometry of the protein, and of peptides obtained by cleavage with EndoLysC proteinase, chymotrypsin and cyanogen bromide. This is the first complete primary structure of a functional unit c from a gastropod hemocyanin. KLH2-c consists of 420 amino acid residues. Circular dichroism spectra indicated approx. 31% β-sheet and 29% α-helix contents. A multiple sequence alignment with other molluscan hemocyanin functional units revealed average identities between 41 and 49%, but 55% in case of Octopus he…
Detection and localisation of disulphide bonds in a synthetic peptide reproducing the sequence 1-30 of Par j 1.0101 by electrospray ionisation mass s…
2001
The structural characterisation of a synthetic peptide reproducing the sequence 1–30 of Par j 1.0101, a major allergenic protein present in the pollen of Parietaria judaica, by combined use of chemical and enzymatic cleavage, reversed-phase high-performance liquid chromatography (RP-HPLC) and electrospray ionisation mass spectrometry (ESI-MS), is described. Direct ESI-MS of the synthetic peptide after reaction with methyl iodide showed that the product is a mixture of two peptides: one form in which two out of the four cysteine residues present in the sequence are oxidised and a minor amount of another form in which all the cysteines are fully reduced. It was ascertained, using the combined…
High yield recombinant production of a self-assembling polycationic peptide for silica biomineralization.
2015
We report the recombinant bacterial expression and purification at high yields of a polycationic oligopeptide, P5S3. The sequence of P5S3 was inspired by a diatom silaffin, a silica precipitating peptide. Like its native model, P5S3 exhibits silica biomineralizing activity, but furthermore has unusual self-assembling properties. P5S3 is efficiently expressed in Escherichia coli as fusion with ketosteroid isomerase (KSI), which causes deposition in inclusion bodies. After breaking the fusion by cyanogen bromide reaction, P5S3 was purified by cation exchange chromatography, taking advantage of the exceptionally high content of basic amino acids. The numerous cationic charges do not prevent, b…
Catalytic triad of microsomal epoxide hydrolase: replacement of Glu404 with Asp leads to a strongly increased turnover rate
1998
Microsomal epoxide hydrolase (mEH) belongs to the superfamily of α/β-hydrolase fold enzymes. A catalytic triad in the active centre of the enzyme hydrolyses the substrate molecules in a two-step reaction via the intermediate formation of an enzyme-substrate ester. Here we show that the mEH catalytic triad is composed of Asp226, Glu404 and His431. Replacing either of these residues with non-functional amino acids results in a complete loss of activity of the enzyme recombinantly expressed in Saccharomyces cerevisiae. For Glu404 and His431 mutants, their structural integrity was demonstrated by their retained ability to form the substrate ester intermediate, indicating that the lack of enzymi…
Modulation of type II collagen-induced arthritis in DBA/1 mice by intravenous application of a peptide from the C1q-A chain.
1992
In this report we are able to show that intravenous (i.v.) application (day 0) of a nonapeptide (residues 26-34) from the human C1q A-chain (designated peptide A-C1q) prior to intradermal (i.d.) administration of chicken type II collagen (CII) in arthritis-susceptible DBA/1 mice (H2q), leads to abrogation of polymorphonuclear neutrophil (PMN) invasion into the joints. This nonapeptide exhibits epitope characteristics and high homology to residues 137-147 of CB11 (a cyanogen bromide fragment of chicken CII, known to contain both arthritis inducing and suppressing determinants). Arthritis index was lowest in animals pretreated i.v. with CII (as internal control), though animals pretreated i.v…