Hensens O D, Dewey R S, Liesch J M, Napier M A, Reamer R A, Smith J L, Albers-Schönberg G, Goldberg I H
Biochem Biophys Res Commun. 1983 Jun 15;113(2):538-47. doi: 10.1016/0006-291x(83)91759-x.
Spectroscopic evidence suggests the presence of a highly strained ether ring (Fig. 1) (possibly an epoxide) in the C12-subunit of the previously determined partial structure 2a (Fig. 2) of the major neocarzinostatin chromophore (NCS-Chrom A) which completes assignment of all the oxygens in the molecule. The main product from mercaptan treatment suggests opening of the ether ring involving the addition of one molecule of mercaptan as well as reduction of the C12-substructure, whereas a parallel two-step reduction occurs on NaBH4 treatment. Both reactions occur with rearrangement of the C12-substructure and the implication for the mechanism of action of NCS-Chrom A in DNA strand scission activity is discussed. The evidence suggests a downward revision of the molecular formula for NCS-Chrom A as well as minor components B and C by two protons.
光谱证据表明，在主要新制癌菌素发色团（NCS-Chrom A）先前确定的部分结构2a（图2）的C12亚基中存在高度应变的醚环（图1）（可能是环氧化物），这完成了分子中所有氧原子的归属。硫醇处理的主要产物表明醚环打开，涉及一分子硫醇的加成以及C12亚结构的还原，而在硼氢化钠处理时会发生平行的两步还原。这两个反应都伴随着C12亚结构的重排，并讨论了其对NCS-Chrom A在DNA链断裂活性中作用机制的影响。证据表明，NCS-Chrom A以及次要组分B和C的分子式应向下修正两个质子。
