Differentiation among the four diastereomers of benzyloxycarbonyl-protected γ-hydroxyornithine in negative-ion fast atom bombardment mass spectrometry
摘要:
AbstractDiscrimination among the four γ‐hydroxyornithine diastereomers was studied by fast atom bombardment mass spectrometry (FABMS). It is impossible to distinguish among the four diastereomers of this amino acid by positive‐ and negative‐ion FAB and collisionally activated dissociation MS, but benzyloxycarbonyl group protection of the α‐ and δ‐amino groups in γ‐hydroxyornithine allows differentiation among the diastereomers in negative‐ion FABMS. The negative‐ion mass spectra of benzyloxycarbonyl‐protected γ‐hydroxyornithine diastereomers showed differences among the abundances of the molecule ion [M – H]‐, the dehydrated ion [M — H — H2O]‐ due to the loss of the γ‐hydroxyl group and the fragment ions formed from both [M — H]‐ and [M — H — H2O]‐ ions. On the other hand, no difference was found between the fragmentations of the benzyloxycarbonyl‐protected enantiomers of ornithine in negative‐ion FABMS. These results indicate that the orientation of the γ‐hydroxyl group and the existence of two benzene rings in the benzyloxycarbonyl group are important factors which are responsible for the fragmentations of the four benzyloxycarbonyl‐protected γ‐hydroxyornithine diastereomers in negative‐ion FABMS. These studies also showed that the negative‐ion FABMS for benzyloxycarbonyl‐protected γ‐hydroxyornithine diastereomers is a useful method for determining the configuration of each diastereomer of γ‐hydroxyornithine.
γ-Hydroxyarginine, a New Guanidino Compound from a Sea-cucumber. I. Isolation and Identification
作者:Yoshimasa Fujita
DOI:10.1246/bcsj.32.439
日期:1959.5
A new guanidino compound was isolated from a sea-cucumber, Polycheira rufescens, and identified as γ-hydroxyarginine. γ-Hydroxyornithine and γ-guanidino-β-hydroxybutyric acid produced enzymically from the guanidino compound were also isolated and identified. It was, further, concluded that the new guanidino compound susceptible to arginase and l-amino acid oxidase should be γ-hydroxy-l-arginine, although the configuration of the γ-hydroxy group was not yet decided.
AbstractDiscrimination among the four γ‐hydroxyornithine diastereomers was studied by fast atom bombardment mass spectrometry (FABMS). It is impossible to distinguish among the four diastereomers of this amino acid by positive‐ and negative‐ion FAB and collisionally activated dissociation MS, but benzyloxycarbonyl group protection of the α‐ and δ‐amino groups in γ‐hydroxyornithine allows differentiation among the diastereomers in negative‐ion FABMS. The negative‐ion mass spectra of benzyloxycarbonyl‐protected γ‐hydroxyornithine diastereomers showed differences among the abundances of the molecule ion [M – H]‐, the dehydrated ion [M — H — H2O]‐ due to the loss of the γ‐hydroxyl group and the fragment ions formed from both [M — H]‐ and [M — H — H2O]‐ ions. On the other hand, no difference was found between the fragmentations of the benzyloxycarbonyl‐protected enantiomers of ornithine in negative‐ion FABMS. These results indicate that the orientation of the γ‐hydroxyl group and the existence of two benzene rings in the benzyloxycarbonyl group are important factors which are responsible for the fragmentations of the four benzyloxycarbonyl‐protected γ‐hydroxyornithine diastereomers in negative‐ion FABMS. These studies also showed that the negative‐ion FABMS for benzyloxycarbonyl‐protected γ‐hydroxyornithine diastereomers is a useful method for determining the configuration of each diastereomer of γ‐hydroxyornithine.
Synthesis of Four Stereoisomers of γ-Hydroxyarginine<i>via</i>the Corresponding Isomers of γ-Hydroxyornithine
作者:Koichi Mizusaki、Satoru Makisumi
DOI:10.1246/bcsj.54.470
日期:1981.2
estimated to be 68% erythro and 32% threo isomers and that of the product from D-histidine 65% erythro and 35% threo isomers by automatic amino acid analysis after conversion of the basic amino acids into neutral Nδ-acetyl derivatives. The diastereoisomers of each γ-hydroxyorni thine were separated by chromatography on a Dowex 50 column, four optically active isomers being isolated as their hydrochlorides