coefficient for mup 0 503 at 1 mg ml the final concentration of pure murine urinary protein was 48 mg ml in 1 9 ml total yield was 90 mg the final mup sample was stored at 4 u00b0 c prior to nmr analysis nmr analysis of murine urinary protein mup containing l valine u03b1 d 12 cd 13 chd 2 2 a 15 mg sample of l valine u03b1 d 12 cd 13 chd 2 2 labeled mup was dissolved in 650 u03bcl phosphate buffered saline 10 mm potassium phosphate 200 mm sodium chloride to which was added 50 u03bcl deuterium oxide 13 c relaxation rates r 2 and r 1 of 13 chd 2 groups were determined using pulse sequences as described in ishima et al j am chem soc 121 11589 11590 1999 spectral parameters were as follows spectral width in the 13 c dimension 900 hz spectral width in the 1 h dimension 5200 hz number of real data points in the 13 c dimension 128 number of real points in the 1 h dimension 1408 number of transients per t 1 increment 8 probe temperature 298 k prior to two dimensional fourier transformation free induction decays were apodized with cosine bell windowing functions according to known methods the nmr analysis was then repeated following addition of the small molecule ligand 1 u03bcl of isobutyl pyrazine or 1 u03bcl of isopropyl pyrazine to separate solutions of mup the data shown below in tables i and ii and in fig8 were obtained clearly showing the changes in t1 and t2 values obtained on addition of these small molecule ligands the relaxation data obtained in the presence of the ligands 2 methoxy 3.