Univalent metal ions such as Na+, K+ and Cs+ can enhance not only the cyclization yields of some linear pentapeptides and heptapeptide but also their cyclization rates while some bivalent and trivalent metal ions such as Mg2+, Ca2+, Zn2+, Fe2+, Ni2+ and Cr3+ elevate neither the cyclization yields nor the cyclization rates and some of them prevent the cyclization.
而一些二价和三价
金属离子,如 Mg2+、Ca2+、Zn2+、Fe2+、Ni2+ 和 Cr3+,既不提高环化产率,也不提高环化速率,有些甚至会阻碍环化。