Acta biologica et medica Germanica 

About: Acta biologica et medica Germanica is an academic journal. The journal publishes majorly in the area(s): Insulin & Cytochrome. It has an ISSN identifier of 0001-5318. Over the lifetime, 1605 publications have been published receiving 6721 citations.

Reliable micromethod for determination of the protein content in tissue homogenates

Abstract: A micromodification for protein determination in tissue material using Amido black 10 B is described. Compared with the method of LOWRY et al. it requires a comparable time expenditure, but has three principal advantages: 1) it is 5-10fold more sensitive; 2) the calibration curve is linear over a virtually unlimited range; 3) it is feasible in the presence of a number of substances frequently used in protein analyses and making difficult or impossible measurement according to LOWRY et al.

The insulin-releasing activity of the tropical plant momordica charantia.

Abstract: An aqueous extract from the unripe fruits of the tropical plant Momordica charantia was found to be a potent stimulator of insulin release from beta-cell-rich pancreatic islets isolated from obese-hyperglycemic mice. The stimulation of insulin release was partially reversible. It differed from that of D-glucose and other commonly employed insulin secretagogues in not being suppressed by L-epinephrine and in even being potentiated by the removal of Ca2+. This anomalous behaviour was not associated with general effects on the metabolism of the beta-cells as indicated by an unaltered oxidation of D-glucose. Studies of 45Ca fluxes suggest that the insulin-releasing action is the result of perturbations of membrane functions. In support for the idea of direct effects on membrane lipids, the action of the extract was found to mimic that of saponin in inhibiting the Ca2+/H+ exchange mediated by the ionophore A23187 in isolated chromaffin granules and release Ca2+ from preloaded liposomes.

Cathepsin H: an endoaminopeptidase from rat liver lysosomes.

Abstract: 1. Cathepsin H is an endoaminopeptidase belonging to the group of thiol enzymes. It was purified from rat liver lysosomes by gel filtration on Sephadex G-75, chromatography on CM-Sephadex C-50, on DEAE-Cellulose DE-52 and subsequently on an organomercurial absorbent. 2. The molecular weight of cathepsin H was found to be 28,000 and the isoelectric point was estimated to be at pH 7.1 by analytical isoelectric focusing. 3. Cathepsin H has to be designated as endoaminopeptidase, because it catalyzes the hydrolysis of proteins, N-terminal substituted proteins and amino acid derivatives, respectively, as well as of peptides of various chain length and N-terminal free amino acid derivatives. Cathepsin H shows amidase and esterase activity, but it does not show carboxypeptidase activity. The finding of the amino- and endopeptidase nature of cathepsin H has been revealed mainly by the results obtained with inhibitors and by the rather high temperature stability of the enzyme. The chlormethyl ketone of leucine proves to be the strongest inhibitor of the aminopeptidase as well as of the endopeptidase activity, whereas leupeptin endopeptidase activity and endopeptidase substrates inhibit competitively the aminopeptidase activity. 5. Cathepsin H shows highest activity at pH 6.0 in the presence of 1--5 mM GSH and EDTA. 6. The enzyme is stable for several months at slightly acid pH values in a deep frozen state.