Ulevostinag (isomer 1)

DNA拓扑学异构体 DNA topological isomer， DNA topoisomer

　　 具有双螺旋结构的 DNA分子，对于二条多核苷酸链的缠绕的程度等有各种形状的拓扑学异构体。例如将不具裂缝的双链环状 DNA的一个链切断，将其一端钻入未切断的链中，然后再使之与原来的一端（头）结合，则可给 DNA分子的整体带来扭曲变形，由于将双链 DNA进一步扭曲而形成超螺旋（参见闭环 DNA），或一侧的链卷到另一侧链上的方式，使 DNA骨架上积累的应变能成为最少。此时，根据向链中钻进的方向（将螺旋反卷的方向或其逆方向）和次数等，形成高级结构上的多样性。这种作为超螺旋 DNA

Enzymatic Production of D-Amino Acids

to obtain either D- or L-amino acids from D,L-mono-substituted hydantoin derivatives. The initial enzymatic reaction step of D,L-mono-substituted hydantoin hydrolysis is catalyzed by a D-hydantoinase after the subsequent racemization of L-isomer to D-isomer

The Chemical Synthesis of -Conotoxins and Structurally Modified Analogs with Enhanced Biological Stability

in structure–activity relationship studies is complicated by the possibility of three disulfide bond isomers, where inefficient folding methods can lead to a poor recovery of the pharmacologically active isomer. In order to achieve