dl-alpha-methyl ornithine , a competitive inhibitor of ornithine decarboxylase ( l-ornithine carboxylyase , ec 4.1.1.7 ) of hepatoma tissue culture cells , blocks the usual increases of putrescine and spermidine concentrations in these cells , and causes a rapid fall in the levels of putrescine which is followed by a striking decrease of spermidine .
C0037871
concentrations
C0034170
putrescine