Treatment of adrenal iron-sulfur protein (adrenodoxin) with urea and guanidine HCI results in a deterioration reaction that proceeds through at least two intermediate stages yielding the completely denaturated, colorless protein. The first transient state exhibits a circular dichroism maximum at 470 rnp which is shifted to a longer wave length than that of the native protein (440 mp) ; at 470 r...

A dipeptide-based urea-amide tertiary amine (DP-UAA) was shown to be an effective Brønsted base catalyst for the first asymmetric annulation reaction between 5H-thiazol-4-ones and N-itaconimides. High levels of enantioselectivity (up to 99% ee) and diastereoselectivity (>19:1 dr) were obtained for a series of spirocyclic 1,4-sulfur-bridged piperidinone-based succinimides.

In the title compound, 2C5H12N+·SO42-·2C3H8N2S, the C=S groups of the two independent 1,3-di-methyl-urea mol-ecules and the sulfur atom of the anion lie on twofold axes. The packing is centred on bis-(piperidinium) sulfate ribbons parallel to the c axis; the cations are hydrogen bonded to the sulfate by N-H⋯O and C-H⋯O inter-actions. The 1,3-di-methyl-urea mol-ecules are also hydrogen bonded to...

Mutants of rhodanese (EC 2.8.1.1) which substitute serine residues for each of the 4 cysteine residues have been studied to determine the roles of cysteines in the structure and function of the enzyme. The proteins compared in these studies were: the wild-type, C63S, C247S, C254S, C263S, C254S/C263S, and C63S/C254S/C263S. These current studies show that cysteine 247 is the only cysteine require...

Experiments were conducted to estimate the threonine requirement of pigs weighing 5 to 15 kg and to determine whether excess methionine increased the threonine requirement. Feeding .70% dietary threonine in Exp. 1 maximized (P<.01) gain/feed and minimized (P<:01) plasma urea N. Plasma threonine was increased (P<.01) by threonine supplementat ion and the rate of increase accelerated above .65% d...