Synthesis of inositol glycans for insulin signal transduction studies and the study of the mechanism of cyclopropane fatty acid synthetase of E. coli

Insulin is a hormone which regulates numerous cellular metabolic activities by initiating a complex array of intracellular communication signals. As part of insulin's communication process, a molecule believed to be an insulin 'second messenger' is released into the cellular fluid. The putative 'second messenger' (also referred to as an inositol phosphate glycan, IPG) resemblances the well characterized GPI membrane anchor molecules which possess an inositol, a phosphate, an amino sugar and numerous mannoses. Described within is the synthesis of mannose glycosyl donors of truncated GPI membrane anchors. The mannose monomer, 2,3,4,6-tetra-O-benzyl-(;Cyclopropane fatty acids (CFAs) are quite prevalent in nature, yet their physiological role is not known. The enzyme which catalyzes the production of CFAs is cyclopropane fatty acid synthetase (CFA synthetase). Described within is the in vitro study of the mechanism of CFA synthetase from E. coli. This in vitro study required pure CFA synthetase (obtained from an overproducing strain of E. coli) and deuterium labeled SAM. Preliminary in vitro studies found no deuterium exchange of SAM-d;As part of the converging synthesis towards the production of truncated GPI membrane anchors, D-myo-inositol derivatives were produced. The procedure involved the regioselective dibutyl tin oxide-promoted acylation of racemic 1,2:5,6-dicyclohexylidene-myo-inositol (2) with 1-(S)-(...