Reaction of 2,4,6-Triphenyl-3,4-dihydro-2H-1,2,4,5-tetrazin-1-yl with hydroquinone

A kinetic study has been made of the reaction between 2,4,6-triphenyl- 3,4-dihydro-2H-1,2,4,5-tetra zin-1-yl and hydroquinone. The results showed that this reaction is reversible and involves two steps. The activation energies for the forward and backward reactions are 45.2 and 18.0 kJ mol-1, respectively.

Gel electrophoresis of amylose in the presence of sodium dodecyl sulfate

It has been shown that sodium dodecyl sulfate (SDS) is capable of forming stable complexes with amylose and that fractionation of short-chain amyloses can be effected by SDS-gel electrophoresis. Using a well-defined smylose fraction (molecular weight 4,000), the thermodynamic parameters pertaining to SDS-amylose interaction have been evaluated by means of frontal gel chromatography. The results are as follows: association constant (K)=5.0 times 10-3-M-minus 1 at 25 degrees (pH 9.4); standard free energy change (delta G degrees)=-5.1 kcal/mole; standard enthalpy change (delta H degrees)=-5.8 kcal/mole; standard entropy change (delta Sdegrees)=-2.3(e.u.) and the maximum number of binding sites for SDS (n)=1. In the presence of 0.5--1 percent SDS, amylose migrates toward the anode upon gel electrophoresis, giving a compact band. High resolution of amylose fractions (released by treatment of amylopectin with debranching enzyme) has been attained using pore-size gradient gel electrophoresis.

Production of coenzyme A by Sarcina lutea

To develop an efficient method for the production of coenzyme A (CoA), optimal conditions for its formation from pantothenic acid, cysteine, and adenine were studied. A number of microorganisms were screened for production of CoA. Strains belonging to the genera Sarcina, Bacillus, Microbacterium, Micrococcus, and Serratia accumulated CoA. Among these, Sarcina lutea was selected as the best organism, and the culture conditions for the production of CoA were investigated with this organism. Under optimal conditions, 600 mug of CoA per ml was accumulated in the culture broth. CoA was readily isolated in high purity by the use of charcoal, diethylaminoethyl-cellulose, Sephadex G-25, and Dowex-50. Yields of isolated CoA were over 33% from culture broth.

Enzymatic production of urocanic acid by Achromobacter liquidum

To develop an efficient method for the production of urocanic acid, optimal conditions for the production of microbial L-histidine ammonia lyase and for the conversion of L-histidine to urocanic acid by this enzyme were studied. A number of microorganisms were screened to test their ability to form and accumulate urocanic acid from L-histidine. Achromobacter liquidum was selected as the best organism. With this organism, enzyme activity as high as 2.0 units/ml could be produced by a shaking culture at 30 C in a medium containing glucose, urea, potassium phosphate, L-histidine, yeast extract, peptone, and inorganic salts. Appropriate addition of a surface-active agent to the reaction mixture shortened the time required for the conversion. A large amount of L-histidine was converted stoichiometrically to urocanic acid in 48 h at 40 C. Accumulated urocanic acid was readily isolated in pure form by ordinary procedures with isoelectric precipitation. Yields of isolated urocanic acid of over 92% from L-histidine were easily attainable. When the culture of Achromobacter liquidum was added to DL-histidine, D-histidine and urocanic acid were simultaneously obtained in high yields.