| The primary structure of the hemoglobin from the backswimmer Buenoa scimitra has been assigned. Reversed phase HPLC was used to purify the intact hemoglobin and enzymatic digests. Mass spectrometric techniques and proteolytic digestions were extensively employed in this study. Liquid chromatography/mass spectrometry was used in the analysis of peptidase digests. The results indicate that the hemoglobins from Buenoa scimitra and Buenoa margaritacea have almost identical sequences. The amino acid at position-98 is lysine for the hemoglobin from Buenoa margaritacea whereas it is arginine for Buenoa scimitra. A 3-D protein homology modeling structure for Buenoa scimitra hemoglobin has been obtained using Quanta 4.1.; The technique of analytical high-speed countercurrent chromatography coupled with electrospray ionization mass spectrometry (HSCCC/ESIMS) has been developed for the first time, and its performance has been evaluated in terms of chromatography and mass spectrometry. This system demonstrated the capability and resolving power of HSCCC in the separation of mixtures and utilized ESIMS as a detector with continuous detection and high sensitivity. Application of this HSCCC/ESIMS system was illustrated by the separation, detection, and structure characterization of drugs, natural products and metabolites. The study demonstrated that LC/MS offered better resolution and less peak broadening in the analysis of trace-level compounds, but that HSCCC/MS could be used in both microanalysis and large scale preparation.; An attempt was made to isolate urease inhibitors from commercial Yucca schidigera extract. Trans-3,3{dollar}spprime{dollar},5,5{dollar}spprime{dollar}- tetrahydroxy-4-methoxystilbene was isolated and its structure was assigned. Biological tests indicated that it was a urease inhibitor, and that it was also active against the L1210 murine leukemia cell line. The enzymatic assay indicated, however, that Cu{dollar}sp{lcub}2+{rcub}{dollar} (CuSO{dollar}sb4{dollar}), which is one of the additives in the commercial Yucca schidigera extract, showed potent urease inhibition activity. |
