Lewis-Randall to McMillan-Mayer conversion for the thermodynamic excess functions of solutions. Part II. Excess energy and volume

Derivations are given for the equations expressing the McMillan-Mayer functions in terms of Lewis-Randall functions.     

A RAPID ASSAY FOR DNA PHOTOLYASE USING A MEMBRANE-BINDING TECHNIQUE*

Abstract— A rapid assay for DNA photolyase was developed that makes use of the membrane binding technique of A. D. Riggs, H. Suzuki and S. Bourgeois, J. Mol. Biol. 48 , 67–83 (1970). The complex formed between UV-irradiated bacteriophage T7 DNA-³H and the enzyme is trapped on a nitrocellulose filter after a five-minute equilibration and is counted. Using this technique, one can calculate the molar concentration of enzyme in an enzyme preparation and the saturation constant (K) for the complex formation. The latter value is 2.6 cyclobutadipyrimidines per genome (T7) for yeast DNA photolyase; thus approximately 5.2 dipyrimidines/genome are necessary for the full retention of the DNA on the membrane. The speed and reproducibility of the new method makes it a convenient one for assaying column effluents and as many as one hundred samples can be handled routinely in an afternoon.     

Separation of amines by ligand exchange: Part IV ligand exchange with chelating resins and cellulosic exchangers

Chelating, sulfonic and cellulosic exchangers were compared in ligand exchange chromatography. Chelating resins retain metal ions the best, but have a low ligand binding capacity. Cellulosic exchangers show excessive metal leakage. Sulfonated polystyrene resins loaded with nickel ions give best results in most cases. Data are presented on ligand exchange chromatography of simple aliphatic amines, hydrazine and substituted hydrazines, purine and pyrimidine bases.