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Biomedical subjects

F Lottspeich

Publications and source records attributed to F Lottspeich.

At least 379 records · Page 21Linked to original sources
PubMed1983

Hemocyanins in Spiders, XVIII. Complete amino-acid sequence of subunit e from Eurypelma californicum hemocyanin.

The complete amino-acid sequence of subunit e of the hemocyanin from the tarantula, Eurypelma californicum, was determined by a combination of manual and automated methods. By limited proteolysis with chymotrypsin, two large fragments (e-CHn 29 and e-CHn 42) were obtained. The large peptides were further cleaved with cyanogen bromide, trypsin (with and without prior blocking of lysine residues), chymotrypsin, Staphylococcus aureus proteinase, Astacus fluviatilis proteinase, or 25% formic acid. The complete chain comprises 621 residues. A remarkable feature of the sequence is a hexapeptide -His-His-Trp-His-Trp-His- which is believed to take part in the binding of copper.

Amino Acid Sequence↗
PubMed1983

Structural aspects of human kininogens.

Kininogens have been purified from human plasma to apparent homogeneity. Native human LMW kininogen is a single-chain (glyco-) protein of molecular weight 68,000, which is converted to a two-chain protein by limited proteolysis with tissue kallikrein to form a heavy chain (Mr 62,000) and a light chain (Mr 4,000). Human HMW kininogen represents a single chain (glyco-)protein of Mr 114,000 which is split into two chains of similar size (H-chain of Mr 58,000 and L-chain of Mr 62,000) by limited proteolysis with tissue kallikrein. Sequence analysis of the isolated L-chain of human MW kininogen indicates a partial homology to the corresponding fragment-1.2 of bovine HMW kininogen. Purified kininogens readily form self-aggregates ranging from dimer to hexamer (HMW kininogen) and from dimer to decamer (LMW kininogen), respectively. Self-association is completely reversible in the presence of dissociating agents. Preliminary evidence suggests that oligomerisation is mediated by the H-chain common to the two types of kininogens.

Amino Acid Sequence↗
PubMed1982

Hemocyanins in spiders, XVII. A presumptive active-site sequence of arthropod hemocyanins.

Peptides containing the sequence -His-His-Trp-His-Trp-His- have been isolated from the subunits e and a of tarantula (Eurypelma californicum) hemocyanin and III B of Limulus polyphemus hemocyanin. In view of the published spectroscopic and titration data on the copper-polypeptide complex and the strong quenching effect of oxygenation on hemocyanin fluorescence, it is concluded that this sequence represents the major part of the active site of Eurypelma, Limulus, and possibly other arthropod hemocyanins.

Amino Acid Sequence↗
PubMed1982

Interaction of human alpha 1-proteinase inhibitor with chymotrypsinogen A and crystallization of a proteolytically modified alpha 1-proteinase inhibitor.

Human alpha 1-proteinase inhibitor (alpha 1-PI) can form very stable complexes with chymotrypsinogen A or chymotrypsin if limited proteolysis by a contaminant proteinase is prevented with diisopropyl fluorophosphate. The contaminant proteinase cleaves the alpha 1-PI component in the alpha 1-PI-chymotrypsinogen A complex close to its N-terminus, between threonine-11 and aspartate-12 and the chymotrypsinogen A part between tyrosine-146 and threonine-147. By this modification the complex becomes unstable and dissociates into modified alpha 1-PI and neo-chymotrypsinogen A. A tritium labelling experiment shows that the contaminant proteinase is present in a 0.5-1.0% (w/w) ratio in the inhibitor preparation. These experiments indicate that alpha 1-PI is not a temporary inhibitor for these enzymes, as assumed by other authors. Isolated modified alpha 1-PI can be crystallized as tetragonal bipyramides from 2.6M sodium potassium phosphate pH 8.0. The crystals are suitable for three dimensional X-ray structure analysis. In spite of the cleavage of the susceptible peptide bond by chymotrypsinogen A, the C-terminal 3.6 kDa cleavage peptide remains tightly bound to the inhibitor by means of non-covalent interactions. In accordance with the result of the known complete amino-acid sequence of the inhibitor this finding offers an alternative explanation to the suggestion of alpha 1-PI being a double headed inhibitor. Isolated neo-chymotrypsinogen A can be activated to active chymotrypsin and can form a very labile 1 : 1 complex with alpha 1-PI, which dissociates rapidly into inactive inhibitor and neo-chymotrypsinogen.

Amino Acid Sequence↗
PubMed1982

Improved purification and N-terminal amino acid sequence determination of the contact site A glycoprotein of Dictyostelium discoideum.

On aggregating cells of Dictyostelium discoideum a specific glycoprotein is expressed which is absent from growth phase cells of this organism. The glycoprotein has been related to cell surface antigens, called contact sites A, that are defined by their reaction with aggregation blocking antibody fragments. In the present paper an improved purification scheme for the glycoprotein is described and its N-terminal sequence is given. The purification has been monitored by use of a monoclonal antibody. The contact site A glycoprotein has the properties of an integral membrane protein.

Amino Acid Sequence↗
PubMed1981

Analysis of human fibrinopeptides by high-performance liquid chromatography.

During coagulation, fibrinogen is cleaved by thrombin, whereby fibrin and low molecular mass peptides, the so-called fibrinopeptides, are released. A novel method, employing high-performance liquid chromatography, has been developed for the separation and quantitation of these peptides. For the chromatography a reversed phase column was used. The fibrinopeptides were detected by their UV-absorption at 210 nm, peptides released from 0.1 mg of fibrinogen being easily detected. The procedure offers for the first time the possibility of determining all human fibrinopeptides and their degradation products in a single analysis. It is eminently suited for fibrinopeptide preparation and studies of fibrinopeptide release kinetics and genetically abnormal fibrinopeptides.

Chromatography, High Pressure Liquid↗
PubMed1980

Hemocyanins in spiders, X. Limited proteolysis of chain e of Eurypelma hemocyanin and partial sequence of two large fragments.

The polypeptide chain e of the homocyanin from the spider Eurypelma californicum was isolated by ion exchange chromatography. Incubation of the undenatured protein with chymotrypsin, subtilisin, or trypsin resulted in a small number of large fragments which were easily isolated after denaturation. Of the chymotryptic peptides e-Chn-29 was found to be N-terminal, and e-Chn-42 C-terminal. These peptides were characterized by their N-terminal amino acid sequences. The N-terminal sequence of subunit e shows homologies with other arthropod hemocyanins.

Amino Acid Sequence↗
PubMed1980

N-Terminal amino acid sequence of boar sperm acrosin. Homology with other serine proteinases.

Boar acrosin with a molecular weight of 38,000 had been isolated. An N-terminal amino acid sequence of 52 residues was determined on the S-carboxymethylated material. The protein contains a single peptide chain. Up to 48% of the positions in the sequence show identity with those of some serine proteinases. The highest degree of homology was found at the comparison with plasmin and chymotrypsin. The N-terminus of acrosin corresponds to that of a serine proteinase in the activated form. The N-terminal amino acid is valine.

Acrosin↗
PubMed1980

Identification of the phenylthiohydantoin derivatives of amino acids by high pressure liquid chromatography, using a ternary, isocratic solvent system.

In recent years high-pressure liquid chromatography has found increasing application in protein chemistry for the identification of the phenylthiohydantoin derivatives of amino acids. For routine microsequencing none of the solvent systems so far published have proved ideal for this application. By using a ternary solvent system we have been able to achieve a rapid isocratic separation of the usual amino acid derivatives with the exception of the pair Gln greater than PhNCS/Ser greater than PhNCS. In practice discriminating between these two derivatives is seldom a problem because Gln greater than PhNCS is partially de-amidated during the conversion and is therefore always accompanied by Glu greater than PhNCS. The dependence of the retention times from pH, buffer composition, buffer concentration, and temperature will be discussed.

Amino Acids↗
PubMed1979

Novel opioid peptides derived from casein (beta-casomorphins). I. Isolation from bovine casein peptone.

A material which displayed opioid activity in the guinea pig ileum longitudinal muscle-myenteric plexus preparation was extracted from an enzymatic casein digest into chloroform/methanol. The extract was roughly purified by adsorption/desorption procedures using charcoal and Amberlite XAD-2 resin as adsorbents. A high degree of purity was achieved by high-pressure liquid chromatography of the material on muBondapak C18 and mu-Porasil columns and finally by gel filtration chromatography on a Bio-Gel P-2 column. Several pronase-resistant compounds with opioid activity were obtained.

Animals↗