Biomedical subjects

I Von Zabern

Publications and source records attributed to I Von Zabern.

4 recordsLinked to original sources

PubMed1979

Incompatibility between complement components C3 and C5 of guinea-pig and man, an indication of their interaction in C5 activation by classical and alternative C5 convertases.

The use of heterologous combinations of guinea-pig and human complement components for titration of C5 with convertases of the alternative and classical pathway has been investigated. In addition to the known unfavourable combination of C2hu with C4gp partial incompatibilities were detected between heterologous C3 and C5 as well as between CZhu and C5gp. The incompatibility between heterologous C3 and C5 is of special interest since it indicates an interaction of these two non-enzymic components. Concomitant binding studies have demonstrated that a reduced efficiency of C5 convertases correlates with decreased binding affinity of surface-fixed C3b for C5 when heterologous components are offered. Hence, the present studies give further evidence that surface-bound C3b has the function of a co-factor which binds C5; this interaction is required for C5 activation via the classical as well as the alternative pathway, i.e. by the C3/C5 convertases C42 and C3bB.

Animals↗

PubMed1979

Multiple effects of a diamidine (propamidine) on complement activation.

Propamidine, one of the diamidines used against infections with babesiae has inhibitory and enhancing effects on complement activation as assessed by immune haemolysis of sensitized sheep red cells. Utilization of C1 is powerfully, that of C3 weakly improved by propamidine while activation and/or fixation of C4, C5 and to a lesser degree of C8 and C9 are inhibited. At low concentrations of propamidine (less than 2 mM) the enhancing effects, at higher concentrations the inhibitory effects predominate. Inhibition is produced, in some cases certainly, in others likely, by interference of propamidine with binding properties of complement components. None of the complement enzymes, C1s, C42 or C3bBb was inhibited in its hydrolytic activity. The possible significance of propamidine actions is discussed.

Amidines↗

PubMed1976

Primary and tertiary structure of the principal human adenylate kinase.

1. Human adenylate kinase (isoenzyme AK-1-1) from skeletal muscle is a single polypeptide chain of 194 amino-acid residues with an acetylmethionine at the N-terminus and a lysine at the C-terminus. 2. The primary structure of the enzyme was determined: Ac-Met-Glu-Glu-Lys-Leu-Lys-Lys-Thr-Lys-Ile-Ile-Phe-Val-Val-Gly-Gly-Pro-Gly-Ser-Gly-Lys-Gly-Thr-Gln-Cys-Glu-Lys-Ile-Val-Gln-Lys-Tyr-Gly-Tyr-Thr-His-Leu-Ser-Thr-Gly-Asp-Leu-Leu-Arg-Ser-Glu-Val-Ser-Ser-Gly-Ser-Ala-Arg-Gly-Lys-Lys-Leu-Ser-Glu-Ile-Met-Glu-Lys-Gly-Gln-Leu-Val-Pro-Leu-Glu-Thr-Val-Leu-Asp-Met-Leu-Arg-Asp-Ala-Met-Val-Ala-Lys-Val-Asn-Thr-Ser-Lys-Gly-Phe-Leu-Ile-Asp-Gly-Tyr-Pro-Arg-Glu-Val-Gln-Gln-Gly-Glu-Glu-Phe-Glu-Arg-Arg-Ile-Gly-Gln-Pro-Thr-Leu-Leu-Leu-Tyr-Val-Asp-Ala-Gly-Pro-Glu-Thr-Met-Thr-Arg-Arg-Leu-Leu-Lys-Arg-Gly-Glu-Thr-Ser-Gly-Arg-Val-Asp-Asn-Glu-Glu-Thr-Ile-Lys-Lys-Arg-Leu-Glu-Thr-Tyr-Tyr-Lys-Ala-Thr-Glu-Pro-Val-Ile-Ala-Phe-Tyr-Glu-Lys-Arg-Gly-Ile-Val-Arg-Lys-Val-Asn-Ala-Glu-Gly-Ser-Val-Asp-Glu-Val-Phe-Ser-Gln-Val-Cys-Thr-His-Leu-Asp-Ala-Leu-Lys. 3. When the primary structure of the human enzyme was fitted to the electron density map of porcine adenylate kinase, all nine amino acids which are different in the homologous enzymes from pig and man were located on the surface of the molecule. 4. Precession photographs of crystalline human and of crystalline porcine adenylate kinase corroborated the result that the polypeptide chains of the two enzymes are folded in a closely related manner. 5. The structure of human adenylate kinase incorporates the so-called nucleotide-binding domain which is present in a wide variety of proteins in nature. Some implications of this phenomenom for the molecular biology and the molecular pharmacology of man are discussed.

Adenylate Kinase↗

PubMed1975

Crystalline adenylate kinase from carp muscle.

1. The concentration of adenylate kinase in carp muscle is about 0.3 mg/g. An improved isolation procedure makes use of a dilute solution of the substrates, ATP and AMP, to elute the enzyme from a phosphocellulose column in overall yields of 60% before crystallization. By the hexokinase--pH-stat assay the specific activity is 3550 units/mg. The preparation has been found to be essentially homogeneous by dodecylsulfate gel electrophoresis, isoelectrofocusing and gel filtration. 2. The molecular weight has been determined to be 22000 by several methods. The absorbance of a 1% solution at 280 nm is 6.9 and the isoelectric point by electrofocusing is pH 5.9. 3. The crystals of carp adenylate kinase have the space group P4-1-22 or P4-3-22. 4. The amino acid composition has been determined. There is no tryptophan, no cystine. There is one amino acid residue each of cysteine and histidine which are at or close to the catalytic center. 5. Several peptides derived by tryptic hydrolysis have been isolated and identified with corresponding peptides of porcine adenylate kinase. Consideration is given to histidine and cysteine being a part of the active site.

Adenylate Kinase↗