lly only a single
conformation- probably conformation A or B [8]. On the other
hand, all vicinal coupling constants in the arginine residue are pairwise
almost equal and amount to ca. 6.5 Hz, which suggests that
this fragment may assume all the staggered conformations with
similar probabilities. There was measured pH dependence of 13C
chemical shifts of ASA in water solution and of urine of patient