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Biomedical subjects

K Müller

Publications and source records attributed to K Müller.

At least 469 records · Page 26Linked to original sources
PubMed1975

[Molecular and complex-chemical studies on methemoglobin from Chironomus thummi thummi and various isolated fractions].

1. Six different hemoglobin (Hb) fractions were isolated and characterized from the larvae of Chironomus thummi thummi using column chromatographic procedures. 2. Chromatographic and sedimentation-analytic studies (sedimentation coefficients of 2.0 +/- 0.2 (S)) have shown three Hb fractions to exist basically in a monomeric form. The molecular weight of component M-2 was determined by sedimentation equilibrium technique to be 15,470 +/- 400. The dimeric Hb was found to have sedimentation coefficients of 3.0 +/- 0.1 (S) in the weakly acidic pH region. In alkaline milieu, the reversible dissociation proceeds into the monomeric molecules (S20, W = 1.9 +/- 0.1 (S)). Molecular weights vary between pH 5.7 and 9.8 not only with hydrogen ion concentration, but also with protein concentration in correspondence with a dissociation-association equilibrium consisting of monomers and dimers. 3. For the Hb fraction M-2, a friction ratio of f/fo = 1.03 was calculated, suggesting an almost spherical shape of this protein. In contrast, the dimeric component appears to have a much more asymmetric structure (f/fo = 1.19). 4. The indivdual MetHb fractions bind the ligands: fluoride, imidazole and azide with different affinities.

Diptera↗
PubMed1975

[Accumulation of basic amino acid residues, rate of autolysis and relative length of gut during trypsin evolution (author's transl)].

The study of six trypsins (crayfish, dogfish, horse, pig, sheep, bovine) showed that among these the highest lysine + arginine content and the highest inactivation rate occur in specialized herbivorous animals with extreme length of gut. Since the autocatalytic degradation in trypsins can take place only at lysine or arginine residues, an accumulation of basic amino acids, the increase of the autocatalytic inactivation rate and the relative length of gut might be correlated during the evolution of mammalian trypsins.

Amino Acids↗
PubMed1975

[The influence of infusions of methionine and methionine+glucose on the morphology and function of self-emptying jejunal blind loops in the rat (author's transl)].

The present study was undertaken to investigate whether an amino-acid solution or a mixture of amino acid and sugar could have a nutritive effect on the intestinal mucosa. Self-emptying blind loops of rat jejunum were perfused 3 times daily for 24 or 31 days, through a tube conveyed subcutaneously to the back of the neck, with a Ringer solution or a saline containing methionine and glucose or methionine alone. Methionine infusion induced a significant rise in the villus height of the mucosa of the blind loops, which was accompanied by an increased glucose absorption, as determined in vivo. In mucosal homogenates there was a tendency toward an increase in dipeptidase activity but not in disaccharidase level. Infusion of a mixture of glucose and methionine led to lengthened crypts, as well as larger villi. Glucose transport was again increased, and there was a small rise in both dipeptidase and disaccharidase activities.

Animals↗