Mannosidase acylation

A variety of proteins are acylated by formation of thioesters to cysteine and esters to serine and threonine. Acylation may serve either to anchor the proteins in membranes (e.g., rhodopsin Section 2.3.1) and the mannosidase of the Golgi, or to increase lipophilicity and thus enhance the solubilization of lipids being transported (e.g., the plasma apolipoproteins and milk globule proteins). Proteolipids with fatty acids esterified to threonine residues occur in the myelin sheath in nerves. 

Chemical transformations carried out on the parent alkaloid (-)-162 are surprisingly uncommon when one considers current levels of interest in the therapeutic properties of the compound and its analogs. The stable hydrohalide salts have been described in a patent relating to the compound s antitumor potential 142). Several 2- and 8-0-acyl esters of 162 have been reported 143). The use of the enzyme subtilisin in pyridine permitted selective synthesis of 2-0-butyrylswainsonine (235) from 162 in 23% yield, while catalysis by porcine pancreatic lipase gave 235 (6%) and 1,2-di-O-butyrylswainsonine (236) (31%) 97). Swainsonine has been tethered at C-7 to an agarose matrix for evaluation as an affinity material for mannosidases 144). 

Both were powerful a-mannosidase and B-gluco-A novel aminosugar, N-acyl-kanoscunine, has been Isolated from the antigenic llpo-oligosaccharlde of Mycobacterium kansasii and proposed to be, 6-dldeoxy-2-0-methyl-... 

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