抄録
Malonate added to peptone-meat extract medium has been shown to induce maleate cis-trans isomerase in Alcaligenes faecalis IB-14. This enzyme played an indispensable role in the enzymatic production of L-aspartic acid from maleic acid and ammonia.
Though malonate in the medium inhibited the growth of A. faecalis IB-14 to some extent, cells grown in the medium containing 10-1 M of malonate showed the highest level of the enzyme activity. Specific activity of the enzyme of malonate-grown cells was ap-proximately ten times as strong as that of maleate-grown cells, while, in basal medium-grown cells, cis-trans isomerization of maleate did not occur at all. Maleate was utilized not only as carbon source of the cell growth but also as inducer for the formation of maleate cis-trans isomerase. On the other hand, malonate was not utilized as carbon source and the metabolism of it within the cell was rather restricted within narrow limits. Thus it was concluded that malonate was a gratuitous inducer for the formation of the enzyme, while maleate, which was considerably metabolized, was normal inducer.
It was demonstrated that most of radioactivity of 1-C14-malonate taken up by cells was localized in particle fraction which sedimented at 105, 000×g for 120 minutes, whereas radioactivity of 1-4-C14-maleate was uniformly distributed in both particulate and soluble fractions. Maleate cis-trans isomerase activity, in turn, was detected exclusively in soluble fraction in both malonate and maleate induced cells.
