The role of metal on imide hydrolysis: Metal content and pH profiles of metal ion-replaced mammalian imidase

Cheng Yang Huang, Yuh-Shyong Yang*

*Corresponding author for this work

Research output: Contribution to journalArticle

26 Scopus citations

Abstract

Imidase catalyzes the hydrolysis of a variety of imides. The removal of metal from imidase eliminates its activity but does not affect its tetrameric and secondary structure. The reactivation of the apoenzyme with transition metal ions Co2+, Zn2+, Mn2+, and Cd2+ shows that imidase activity is linearly dependent on the amount of metal ions added. Ni2+ and Cu2+ are also inserted, one per enzyme subunit, into the apoimidase, but do not restore imidase activity. Enzyme activity with different metal replaced imidase varies significantly. However, the changes of the metal contents do not appear to affect the pKas obtained from the bell-shaped pH profiles of metal reconstituted imidase. The metal-hydroxide mechanism for imidase action is not supported based on the novel findings from this study. It is proposed that metal ion in mammalian imidase functions as a Lewis acid, which stabilizes the developing negative charge of imide substrate in transition state.

Original languageEnglish
Pages (from-to)1027-1032
Number of pages6
JournalBiochemical and Biophysical Research Communications
Volume297
Issue number4
DOIs
StatePublished - 7 Nov 2002

Keywords

  • Imidase
  • Metal replacement
  • pH profile
  • Transition metal

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