Cis- and trans-isomers of alpha-hydroxy-alpha,beta-dibenzyl-gamma-butyrolactone lignans 1a,d-g and 2a,c,d were stereoselectively synthesized in good yields based on the electrophilic addition to the metal enolate of alpha-benzyl-gamma-butyrolactone derivatives 1l-o and 3 as a key step. This method was applied to the syntheses of (+/-)-trachelogenin and (+/-)-guayadequiol, representative examples of the trans- and cis-isomers of alpha-hydroxy-alpha,beta-dibenzyl-gamma-butyrolactone lignan series.
B. brevis 47 secretes a vast amount of protein consisting mainly of two kinds with approximate molecular weights of 130,000 and 150,000. The two major extracellular proteins were indistinguishable from those of cell wall protein by SDS-polyacrylamide gel electrophoresis. Based on the results of analysis of amino acid composition, limited proteolysis followed by electrophoresis, and the cross-reactivity of antisera, we conclude that the 130K and 150K extracellular proteins are derived from the respective cell wall proteins. Furthermore, the NH2-terminal amino acid analysis suggests that the two major extracellular proteins are released from the cell wall without any modification of the NH2-terminal portion.
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