Aminoacylase from pig kidney contains no disulfide bonds
Both non-reduced/reduced(NR/R)two-dimensional diagonal SDS-PAGE and NR/R one-dimensional SDS-PAGE showed no disulfide bonds in aminoacylase from pig kidney.Eight and four thiol groups were modified in the native enzyme by 2-chloromercuri-4-nitrophenol(MNP)and Ellman's reagent,5,5'-dithiobis(2-nitrobenzoic add)(DTNB),and another two and six thiol groups could be exposed and modified in 7mol/L guanidine hydrochloride,respectively.The enzyme denatured with guanidine or urea was found to contain a total of ten thiol groups.This is in good agreement with the recently deduced amino acid sequence from cloned cDNA.It is therefore clear that no disulfide bridges exist in aminoacylase from pig kidney.