High resolution HPLC techniques such as affinity chromatography (AC), ion exchange chromatography (IEC), and size exclusion chromatography (SEC) were used successfully for separations of hydrophobic plasma membrane glycoproteins. We have tested a lot of commercially available columns for IEC and SEC and performed the purification of the crude plasma membrane extract with the most suitable colum...

Total urinary porphyrins were eluted from a commercially available anion exchange Chromatographie column with hydrochloric acid and determined spectrophotometrically. For 1 ml samples the optimum concentration range for measurement was found to lie between 0.1 and 1.5 mg of total porphyrin/1 urine. Assay of a single sample takes 12 min. The specificity (measurement at three wave lengths), sensi...

Neurophysin has been separated into seven distinct protein fractions. One of these components had no hormone-binding activity. The fractions that had hormone-binding activity were similar in amino acid composition: their cystine content was in the range 11.5-14.5%. The major component, neurophysin-M, was distinguished from the protein isolated by van Dyke by the presence of methionine and the a...

We describe an improved separation of the isoenzymes of aspartate aminotransferase (EC 2.6.1.1), based on ion-exchange chromatography. Involving the "Fast Protein Liquid Chromatography" system (Pharmacia) with a MonoQ column, this rapid, reproducible method for quantifying the mitochondrial enzyme shows good resolution and sensitivity, and results correlate well with those by an established imm...

With the increasing demand for coenzyme A (CoA) to be used as a substrate in enzyme studies, a need has developed for additional methods of isolating this substance from natural sources. Two methods have been published whereby CoA of reasonably high purity can be prepared (1, 2). Both of these procedures are lengthy and the over-all yields are relatively poor (10 to 30 per cent). One of these m...

Introduction Hydroxyapatite chromatography was introduced in 1956, but despite numerous publications describing its merits as a unique chromatography tool, it has failed to attain the popularity of ion exchange (Tiselius et al. 1956). A number of reasons account for its neglect, most of which are artificial and the remainder obsolete. In practice, it offers a unique assemblage of process charac...

We study the two-band degenerate Hubbard model using the fluctuation exchange approximation (FLEX) and compare the results with quantum Monte Carlo (QMC) calculations. Both the self-consistent and the non-self-consistent versions of the FLEX scheme are investigated. We find that, unlike in the one-band case, in the multiband case, good agreement with the quantum Monte Carlo results is obtained ...

Replica-exchange (RE) algorithms are used to understand physical phenomena--ranging from protein folding dynamics to binding affinity calculations. They represent a class of algorithms that involve a large number of loosely coupled ensembles, and are thus amenable to using distributed resources. We develop a framework for RE that supports different replica pairing (synchronous versus asynchrono...

We illustrate how coupling could occur between surface air and clouds via the global electric circuit – through Atmospheric Lithosphere–Ionosphere Charge Exchange (ALICE) processes – in an attempt to develop a physical understanding of the possible relationships between earthquakes and clouds.