Molecular environment and temperature dependence of hyperfine interactions in sugar crystal radicals from first principles.

The effect of the molecular environment and the temperature dependence of hyperfine parameters in first principles calculations in alpha-d-glucose and beta-d-fructose crystal radicals have been investigated. More specifically, we show how static (0 K) cluster in vacuo hyperfine calculations, commonly used today, deviate from more advanced molecular dynamics calculations at the experimental temperature using periodic boundary conditions. From the latter approach, more useful information can be extracted, allowing us to ascertain the validity of proposed molecular models.

Some new bifunctional reagents for the conjugation of a protein with an amino compound in water.

Five symmetrical bifunctional reagents (I-V) have been synthesized and tested for their usefulness for the conjugation of albumin with tryptophan, in aqueous solution. With I and II about 17, with IV and V about 8 tryptophan residues could be introduced in the native protein. The difference is discussed. Reagent III has a very low solubility in water but may be useful if organic solvents are permissible.