10.1021/tx950065t
The research investigates the quantitative relationships between substrate structure and the catalytic activity of sulfotransferase a (STa), an enzyme that catalyzes the formation of sulfuric acid esters from alcohols. The study aims to understand the specificity of STa for various alcohols, including both endogenous and xenobiotic compounds. Key chemicals involved in the research include benzyl alcohol and a series of benzylic alcohols substituted with n-alkyl groups (CnH2n+1, where n ranges from 1 to 8), primary n-alkanols (CnH2n+1OH, where n ranges from 3 to 16), and various other alcohols such as cholesterol, dehydroepiandrosterone (DHEA), and several phenols. The researchers also used 7-(hydroxymethyl)-12-methylbenz[a]anthracene (HMBA) to study the enzyme's activity with a carcinogenic compound. The study employed methods such as purification of STa, determination of kinetic constants (kcat/Km values), and molecular modeling to analyze the influence of substrate hydrophobicity and steric effects on the catalytic efficiency of STa. The findings revealed that hydrophobicity of the substrate is a major factor contributing to the catalytic efficiency, with optimal catalytic efficiency observed for certain chain lengths of aliphatic alcohols and benzylic alcohols. The study also highlighted limitations in substrate size and the importance of steric effects, providing insights into the enzyme's specificity for different alcohols.
10.1021/ja971291n
The study focuses on the synthesis and investigation of azobenzene phospholipids (APLs) in aqueous dispersions, both in pure form and when mixed with saturated and unsaturated phospholipids. The research explores the structures of the assemblies formed by these APLs, which include various forms such as large plates, and their ability to form "H" aggregates with typical aggregation numbers being multiples of three. The study utilizes techniques like microcalorimetry, dynamic light scattering, cryo-transmission electron microscopy, and reagent entrapment to analyze the assemblies. It also examines the photoreactivity of the azobenzenes, which can photoisomerize to produce cis-rich photostationary states. Interestingly, the cis-azobenzenes do not aggregate and can be reverted back to the trans form through irradiation or thermal means. The research further explores the controlled release of entrapped reagents from vesicles formed by mixed aqueous dispersions of trans-APLs with other phospholipids, demonstrating that photoisomerization can induce reagent release. The study provides insights into how aggregation influences the microstructure and macroscopic properties of the assemblies, with potential applications in drug delivery and other areas requiring photoresponsive materials.
10.1016/S0040-4039(00)97381-7
The research documented in the literature focuses on the selective thermal glycosylation of various alcohols using 2,3,4-tri-O-benzyl-α-L-rhamnopyranosyl chloride and 2,3,4,6-tetra-O-benzyl-α-D-mannopyranosyl chloride to produce α-glycosides with high selectivity. The study builds on previous work involving thermal glycosidation with glucosyl or xylosyl chlorides but introduces a significant improvement in stereoselectivity, particularly with sterically hindered alcohols. The key chemicals involved in this research include the rhamnosyl and mannosyl chlorides as glycosyl donors, various alcohols such as cholesterol, cholestanol, dihydrolanosterol, and others as acceptors, and in some experiments, N,N,N',N'-tetramethylurea (TMU) as an acid scavenger. The process is notable for its simplicity, safety, and economy, as it does not require hazardous metal salts or solvents, making it a practical and environmentally friendly method for glycosylation.
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