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Biomedical subjects

R Geiger

Publications and source records attributed to R Geiger.

At least 145 records · Page 8Linked to original sources
PubMed1976

A kallikrein-specific inhibitor in rat kidney tubules.

A kallikrein inhibitor was found in tubules of the rat kidney and purified by chromatography on Sephadex G-100. The molecular weight of the inhibitor, estimated by gel filtration and dodecylsulfate electrophoresis, is about 4700. It inhibits the following kallikreins: porcine submanidbular and pancreatic kallikrein, rat kidney and urine kallikrein, and human urine and plasma kallikrein. An inhibition of bovine trypsin was not observed.

Animals↗
PubMed1976

A new semisynthesis of human insulin.

A new semisynthesis of human insulin starting from porcine insulin is described. NalphaA1, NalphaB1-di-Boc-desoctapeptide-(B23-30)-insulin bearing 6 free carboxyl groups is coupled with the suitably protected human insulin-(B23-30)-octapeptide. The preferred reaction site is the carboxyl group of ArgB22. Side products are eliminated by extensive chromatographic purification.

Amino Acid Sequence↗
PubMed1976

[(A1-beta-Alanine) insulin].

Starting from porcine insulin, A1-glycine was substituted by beta-alanine. The blood sugar lowering effect of the new analogue in the rabbit is about 45% of that of insulin. The half-maximal binding to partially purified rat liver receptors is about 46%, to transformed human lymphocytes about 54%, compared to insulin.

Alanine↗
PubMed1975

[(A1-D-alanine) insulin (author's transl)].

Starting from porcine insulin, A1-glycine was substituted by D-alanine and by L-alanine for comparison. Replacement of A1-glycine by L-alanine revealed the known decrease in the biological activity. [A1-D-Alanine]insulin, however, has the same blood sugar lowering activity as insulin and is slightly more active in its influence on the glucose uptake into the rat diaphragm. The specific binding to insulin receptors of rat liver is decreased as, compared to insulin, but increased as compared to the L-alanine analogue.

Alanine↗
PubMed1975

[IMP-cyclohydrolase/transformylase from ehrlich-ascites carcinoma (author's transl)].

The IMP-cyclohydrolase/transformylase enzyme was purified from Ehrlich ascites tumor cells by ammonium sulfate fractionation and chromatography on Sephadex G-75 and DEAE-Sephadex. The electrophoretically pure enzyme has a molecular weight of about 350000, estimated by a gel filtration, and an isoelectric point of 6.2. It is composed of 8 subunits with a molecular weight of 46000. Every subunit is composed of two different proteins with a molecular weight of 18000 and 28500. Some further characteristics of the enzyme are reported.

Animals↗
PubMed1975

[The effect of fumaric acid monoethylester on the synthesis of nucleic acids and proteins of PHA-stimulated human lymphocytes (author's transl)].

Fumaric acid monoethylester (FAME) inhibits the incorporation of 14C-Thymidin, 14C-Uridin, 14C-Alanin and 14C-Leucin into acid-insoluble biopolymers of cultivated PHA-stimulated human lymphocytes. At high concentrations of FAME (500 mug/ml culture medium) the inhibition of nucleic acid synthesis is 6 times higher on the average than the inhibition of protein synthesis. However, the application of the cis-isomer, maleic acid monoethylester (MAME), results in an increase of the incorporation rate of the labelled precursors into the RNA and DNA. This is 3.5--9.3 times higher than after application of FAME. The results demonstrate the specific inhibition by FAME. The rate of labelling of nucleic acids is decreased above 10 mug FAME/ml culture medium and in the case of MAME above 50 mug/ml medium. As an explanation of the specific action of FAME its influence on the enzymes of the nucleic acid synthesis, the citric acid cycle or a faulty synthesis of enzymes are discussed.

Alanine↗
PubMed1975

[A new bifunctional reagent for the intramolecular crosslinking of insulin (author's transl)].

Reaction of bis-[2-(succinimidooxycarbonyloxy)ethyl]sulfone [SO2(Eoc-ONSu)2] with insulin in 1N NaHCO3/dimethylformamide forms NalphaA1,NepsilonA1,NepsilonB29-2,2'-sulfonylbis(ethoxycarbonyl)insulin [SO2(Eoc)2-insulin] in 20 - 35% yield. The product can be purified by partition chromatography. After cleavage of the disulfide bridges, reoxidation in very dilute solution reconstitutes about 60% of the original insulin activity. Cleavage of the crosslinking moiety can be achieved with 0.5N NaOH at 0 degrees C in only a few seconds, rendering a biologically fully active insulin.

Binding Sites↗