Showing papers by "Friedrich Lottspeich published in 1980"

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

Abstract: 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.

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

Abstract: 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.

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

Abstract: 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.

β-CASOMORPHINS–NOVEL OPIOID PEPTIDES DERIVED FROM BOVINE CASEIN–ISOLATION AND STRUCTURE

Abstract: Material, showing opioid activity in the guinea pig ileum bioassay, could be obtained by chloroform-metha-nol extraction of casein peptone. The extract was purified by adsorption procedures, high pressure liquid chromatography and gel filtration. Several opioid components could be separated. One of these accounted for over 90% of the total opioid activity and was subjected to structure analysis. It contained a pure heptapeptide, Tyr-Pro-Phe-Pro-Gly-Pro-11e. Evidence for its identity with the opioid principle was obtained by measuring changes in activity on acid hydrolysis, acetylation and enzymatic digestion, all of which altered the peptide structure; in all cases the activity also disappeared. The peptide is highly resistant towards most proteolytic enzymes, even pronase. However, carboxypeptidase γ degrades it, first giving rise to a pentapeptide, Tyr-Pro-Phe-Pro-Gly, which is more active than the heptapeptide, and then a tripeptide, Tyr-Pro-Phe, which is inactive. The sequence of the heptapeptide identified it as a fragment of bovine β-casein. Because of this the opioid peptide was called β-casomorphin.