Amidases are a class of hydrolases,which catalyze the hydrolysis of C—N bonds ofvarious amides to the corresponding carboxylic acids and ammonia.They are ubiquitous in many different types of organisms.According to their amino acid sequences,amidases can be assigned into nitrilase superfamily and amidase signature family.Here,we systematically review the progress of study in molecular structures and catalytic mechanisms of amidases,as well as the specific catalytic processes of specific amidases.All members of the nitrilase superfamily possess the conserved catalytic triad Cys-Lys-Glu,and exhibit similar catalytic processes.The residue Cys is responsible for the nucleophilic attack,Glu acts as a general base,while Lys is involved in the stabilization of the transition states.As for amidase signature family,the conserved catalytic triad is Ser-cisSer-Lys,and the catalytic processes vary from different signature amidases. According to the role of Lys,the catalytic mechanism can be divided into two types:general acid
catalysis and general base catalysis.
JIN Jianqiang,WU Zheming,ZHENG Renchao
. Progress on the catalytic mechanism of amidas[J]. Bulletin of Fermentation Science and Technology, 2017
, 46(3)
: 170
-177
.
DOI: 10.16774/j.cnki.issn.1674-2214.2017.03.009