PubMed Health⌕ Search

Biomedical subjects

W Lergier

Publications and source records attributed to W Lergier.

18 recordsLinked to original sources
PubMed1982

Human low-molecular-weight urinary urokinase. Partial characterization and preliminary sequence data of the two polypeptide chains.

Low-molecular-weight urokinase (molecular weight 33100) was separated by analytical and preparative isoelectric focusing into five major subforms with isoelectric points between 8.7 and 9.6. These subforms are very similar in molecular weight, specific activity, amino acid composition and content of amino sugar and their N-terminal sequence constellation is identical. Low-molecular-weight urokinase consists of two polypeptide chains connected by a single disulfide bridge. The N-terminal region of the heavy chain (calculated Mr 30700) exhibits homology within the first 46 residues analyzed, with the known primary structure of other serine proteases. The mini chain (Mr 2426), whose complete sequence was determined, consists of 21 residues which show homology with the primary structure of the C-terminal region of the plasmin heavy chain. Based on sequence data and homology criteria with serine proteases a single-chain urokinase precursor is postulated having a peptide bond constellation between heavy and light chain region compatible with the requirements for serine protease activation.

Amino Acid Sequence↗
PubMed1981

Comparison of the primary structure of the N-terminal CNBr fragments of human, bovine and porcine plasminogen.

The primary structures of the N-terminal CNBr fragment of human, bovine and porcine plasminogen were determined by automated Edman degradation in a combination of liquid and solid-phase techniques and also by applying the carboxypeptidase method. The comparison of the fragments showed three highly homologous and two variable regions. The heptapeptide sequence responsible for intramolecular interaction is preserved in a conservative region, whereas the sequence of the acidic loop varies considerably between the species. In the bovine and porcine fragments 18 of the 57 residues are exchanged when compared with the fragment of human plasminogen, whereas only 11 exchanges occur between the two fragments of animal origin.

Amino Acid Sequence↗
PubMed1980

alpha 1-Microglobulin from normal and pathological urines.

alpha 1-Microglobulin was purified from normal and pathological urines. Significant differences were found in the amino acid compositions of the alpha 1-microglobulin isolated from these two sources. In addition electrofocusing of alpha 1-microglobulin from normal urine gave rise to two peaks of equal intensity with rather acidic isoelectric points (3.8 and 4.2), whilst alpha 1-microglobulin from pathological urine showed two peaks in a 1:5 ratio with less acidic isoelectric points (4.2 and 4.7). Further charge heterogeneity was also observed in the second peaks from both sources. The sugar compositions were also established, as well as the N-terminal sequences of the alpha 1-microglobulin of both peaks isolated from normal and pathological urines.

Alpha-Globulins↗
PubMed1980

Peptides isolated from human liver with specific inhibitory effects on reassociation/reactivation of in vitro dissociated lactic dehydrogenase (LDH-M4 and -H4) isozymes.

Two different peptides have been purified from human liver, similar to those previously reported (Schoenenberger, G.A., and Wacker, W.E.C. (1966) Biochemistry 5, 1375--1379) to be present in human urine, which may serve as metabolic regulators of lactate dehydrogenase (EC 1.1.1.27) isoenzymes (LDH-M4 = muscle type; LDH-H4 = heart type). By trichloroacetic acid precipitation, ultrafiltration, Sephadex G-25 and Bio-Gel P-2 columns, affinity chromatography on immobilized LDH-isozymes and HPLC two peptides which differed with respect to molecular weight, retention on the affinity columns and amino acid composition were isolated. No effect was observed when native, tetrameric lactate dehydrogenase was incubated with these peptides. However, when lactate dehydrogenase was dissociated to monomers at low pH and allowed to reassociate by adjusting the pH to 7.5 complete inhibition of the reactivation occurred when the inhibitors were incubated together with respective reassociating monomeric isozymes. The two peptides showed no cross-specificity, i.e. each peptide exhibited inhibitory activity only on one of the two isozymes LDH-M4 or LDH-H4. From the amino acid analyses, gel filtrations and PAGE + SDS, molecular weights of 1800 for the M4 and approximately 2700 for the H4 inhibitor were calculated. An apparent Ki of approximately 3 X 10(-5) mM for the H4 and approximately 7 X 10(-5) mM for the H4 inhibitor was estimated. The interaction of the inhibitors with the enzyme system showed strong cooperativity with Hill coefficients of 2.9 (LDH-M4-specific) and 2.4 (LDH-H4-specific). Mathematical modelling of the reassociation and reactivation of lactate dehydrogenase and its specific inhibition by the peptides led to the conclusion that the peptides react with monomers, dimers or a transition state during the tetramerisation process. kappa 1 for the dimerisation step of M4 = 2.0 X 10(5) M-1 . S-1 and of H4 = 8.2 X 10(4) M-1 . S-1; kappa 2 for the tetramerisation step of M4 = 2.8 X 10(5) M-1 . S-1 and of H4 = 1.2 X 10(5) . M-1 S-1, were calculated, the second step still being the faster one (Rudolf, R. and Jaenicke, R. (1976) Eur. J Biochem. 63, 409--417).

Amino Acids↗
PubMed1980

Localization of individual lysine-binding regions in human plasminogen and investigations on their complex-forming properties.

After partial digestion of human plasminogen with elastase, followed by chymotryptic cleavage of one of the fragments produced, two polypeptides with molecular weights of approximately 10 000 and with lysine-binding sites still intact were isolated by means of affinity chromatography and gel filtration. One fragment, which was completely sequenced (88 residues), was identified as the fourth kringle, whereas the other, according to partial sequence analysis represented the first kringle. Equilibrium dialysis against 6-aminohexanoic and yielded for the first kringle one high-affinity binding site (Ka = 60 mM-1) and for the fourth kringle one single low-affinity binding site (Ka = 28 mM-1). Moreover, interactions were detected between the first kringle and the N-terminal CNBr fragment of plasminogen and also fibrin. In these cases an additional lysine-binding site, though of low affinity, appears to be involved. Thus, the first kringle seems to play important roles, structurally by contributing to the maintenance of a compact structure of plasminogen through an intramolecular interaction with its N-terminal polypeptide region, and functionally by increasing the fibrin affinity of Lys-plasminogen (plasminogen lacking the first 76 residues) and plasmin.

Amino Acid Sequence↗
PubMed1976

Investigations on the primary structure of human plasminogen. Further evidence for sequence homology.

NH2-Terminal sequences were determined by the automated Edman method in four fragments which were isolated from a mixture of fragments obtained by CNBr cleavage of human plasminogen. One of the fragments whose sequence was determined over the first 31 residues shows sequence homologies with the fragment that forms the linkage between the plasmin chains and also with the non-thrombin part of prothrombin.

Amino Acid Sequence↗
PubMed1969

The immunogenicity of dinitrophenyl amino acids.

Numerous dinitrophenyl amino acid preparations injected intradermally induced contact hypersensitivity to dinitrochlorobenzene, delayed type skin reactions to DNP-amino acids, and anti-DNP antibodies in guinea pigs. Some DNP-amino adds induced precipitating anti-DNP antibodies in rabbits as well. Some of the DNP-ammo acids studied were regularly immunogenic, possible immunogenic impurities having been excluded by extensive purification procedures. Others were either constantly nonimmunogenic or irregularly immunogenic, e.g., their immunogenicity varying from one preparation lot to another. By means of extensive chemical analyses and the establishment of dose-response curves, we were able to demonstrate in most cases that the immunogenicity was not due to contamination with unreacted dinitrofluorobenzene or other DNP derivatives, to photodecomposition or other degradation products, or to DNP-protein contaminants. Nevertheless, the irregular immunogenicity of several DNP-amino acid preparations can only be explained by a highly immunogenic impurity (or impurities) which we were unable to detect analytically. The regular immunogenicity of some other DNP-amino acids (e.g. di-DNP-L-histidine) appears to be based on a "transconjugation" phenomenon, the DNP group being able to split off from its amino acid carrier and to conjugate secondarily with proteins in vivo and in vitro. Accordingly, the interpretation of some recent data concerning the immunogenicity of low molecular weight hapten-amino acids may have to be reevaluated.

Alkanes↗
PubMedDate not supplied

Inhibition of the reactivation of acid-dissociated lactate dehydrogenase isoenzymes by their aminoterminal CNBr fragments.

The catalytic activity of lactate dehydrogenase isoenzymes (LDH) depends on their tetrameric structure. Stabilization of this quaternary structure is achieved by interaction of the N-terminal part of one subunit with the C-terminal region of the other subunit. The N-terminal peptides from pig M-LDH and H-LDH which are responsible for this stabilization were obtained by CNBr-fragmentation and purification on reversed-phase HPLC. The effect of these peptides on the formation of the quaternary structure of LDH-isoenzymes was investigated by monitoring the reconstitution of the catalytic activity after acid-dissociation. Low concentrations of the N-terminal peptides led to an increased, and high concentrations to a decreased yield of reconstituted LDH activity. The effects of these two peptides were isoenzyme specific. The 32 residue peptide derived from M-LDH showed the highest effect when tested with M-LDH as target enzyme but only a poor effect with H-LDH. On the other side the 33 residue peptide generated from H-LDH showed a moderate effect with both isoenzymes. The effects of the N-terminal LDH peptides are antagonized by the coenzymes NAD+ and NADH. The most significant influence was observed with NAD+ in the M-LDH peptide-M-LDH enzyme system. Comparison of the properties of the reactivation antagonists isolated from human origin with the N-terminal CNBr-peptides of LDH revealed identity in all essential properties, suggesting that the former peptides are generated by degradation of LDH.

Animals↗