Yeast phosphofructokinase exists in several enzymically active, interconvertible forms with molecular weights of 180,000, 370,000, 570,000 and 750,000. With disc-electrophoresis catalytically active aggregation products with molecular weights of more than one million can be detected.In alkaline media fragmentation of phosphofructokinase occurs, leading to a variety of catalytically inactive products. These seem to be oligomers of subunits with 60,000 daltons. A model of the complex subunit structure of yeast phosphofructokinase is suggested. The various catalytically active forms of the enzyme are considered as polymers of 180,000 monomers, which themselves are enzymatically active and which are composed of three 60,000 subunits.

Journal Article↗

PubMed1970

Aggregationsformen der Rinderleberkatalase.

Bovine liver catalase is separated into several distinct bands by electrophoresis in a linear concentration gradient of polyacrylamide. Apparently, disc electrophoresis under these conditions leads to a series of enzymatic active forms of catalase. Their molecular weights are: 248,000; 295,000; 368,000; 486,000; 705,000 respectively. Density gradient centrifugation separates catalase into two components with molecular weights of 252,000 and 316,000. The observed differences in molecular weight distribution between gel-electrophoresis and density gradient centrifugation are discussed.

Journal Article↗

PubMed1969

Molekulargewichtsbestimmungen durch polyacrylamidgelelektrophorese unter verwendung eines linearen gelgradienten.

A new method for molecular weight determination using polyacrylamidegel electrophoresis in a linear gel-concentration-gradient (3-20 degrees ) is described. Plotting the log of molecular weights of several standard proteins against distance of migration or against 3 log of rate of n-dgration reveal linear relationships in ranges of 50.000 - 200.000 or 100.000 - 400.000 Daltons respectively. On this basis, a simple method for molecular weight determination of proteins (accuracy +/- 5 degrees ) has been devised. The method can also be applied for an individual protein in protein mixtures using specific staining procedures.

Journal Article↗

PubMed1968

Some kinetic and molecular properties of yeast phosphofructokinase.

Yeast PFK had a sedimentation coefficient of 16.7 S both in the absence and in the presence of ATP, and did not dissociate even at very low protein concentrations. Sodium dodecyl-sulphate caused dissociation of the protein to sub-units of 3.2 S.The effects of pH on substrate affinities are described. In the presence of UTP, acting as non-inhibiting phosphate donor, the behaviour of the enzyme towards F-6-P was co-operative, with a Hill coefficient of 2.2.

Journal Article↗

PubMedDate not supplied

Lipid peroxidation products in human spermatozoa: detection and pathogenic significance.

Products of lipid peroxidation (Schiff-base products were detected in normal human spermatozoa. During aerobic incubation of the spermatozoa with an oxidant (ferrous sulphate) the peroxides became detectable in increased concentration. Coincidentally with the formation of peroxides the sperm motility declined.

Adult↗

PubMedDate not supplied

Proliferation of human bone marrow cells in vitro: inhibition by Candida albicans components.

We studied the influence of human recombinant granulocyte-macrophage colony-stimulating factor (rhGM-CSF) and Candida albicans (CA) components, either alone or in combination, on the proliferation of human bone marrow cells in vitro (colony-forming assay). The number of colonies per 10(5) bone marrow cells after cultivation with rhGM-CSF [maximal (plateau) colony formation] was: 46.2 +/- 9.1 (n = 6); after cultivation with rhGM-CSF in combination with CA components the numbers of colonies were as follows: 0.05 mg protein/ml, 33.4 +/- 4.6 (n = 3); 0.10 mg protein/ml, 20.8 +/- 3.6 (n = 3). The mechanisms responsible for this inhibition of colony formation are still unknown. They may be of pathogenetic significance in CA infection.

Bone Marrow↗

PubMedDate not supplied

[Electrophoretic examination of protein distribution in guinea pig perilymph].

Perilymph and serum of guinea pigs were investigated using immunoelectrophoresis and polyacrylamide gel electrophoresis. The molecular weights of the perilymph proteins were estimated by electrophoresis in a linear polyacrylamide gel gradient (3-20%). The immunoelectropherograms and the polyacrylamide gel electropherograms of equivalent amounts of perilymph protein and serum protein are nearly the same. The immunological detection of the perilymph proteins indicates that they are serum proteins. The clear identification of the individual proteins fails because of missing monospecific antisera against the individual proteins of guinea pig. High-molecular proteins (range of the molecular weight estimation 67 000-290 000) are also detectable in the perilymph according to the molecular weight estimation.

Animals↗