The methyl ester of succinic semialdehyde (SSA) was examined as a substrate for succinate semialdehyde dehydrogenase (SSADH) from rat brain. It was found that the ester can be oxidized by the enzyme. Values of K(m) for SSA-Me were higher than for those for SSA, and for this substrate the enzyme showed a substrate- dependent inhibition. This finding suggests that the carboxylate group of SSA is not essential in the process of inhibition of SSADH by the substrate. Cyclopropyl analogues of SSA, cis- and trans-1-formyl-cyclopropan-2-carboxylic acids, were also individually tested as substrates of SSADH. Only the trans isomer was found to be oxidized to the corresponding dicarboxylic acid; it inhibited the enzyme in the same range of concentrations as SSA. The above data suggest that, as for γ-aminobutyric acid, SSA is present in an unfolded, transoid conformation at the active site of SSADH.
Studies on analogues of succinic semialdehyde as substrates for succinate semialdehyde dehydrogenase from rat brain / A.G. Manzocchi, P.A. Biondi, C.L. Secchi, E. Santaniello. - In: JOURNAL OF NEUROCHEMISTRY. - ISSN 0022-3042. - 46:6(1986), pp. 1895-1898.
Studies on analogues of succinic semialdehyde as substrates for succinate semialdehyde dehydrogenase from rat brain
A.G. ManzocchiPrimo
;P.A. BiondiSecondo
;C.L. SecchiPenultimo
;E. SantanielloUltimo
1986
Abstract
The methyl ester of succinic semialdehyde (SSA) was examined as a substrate for succinate semialdehyde dehydrogenase (SSADH) from rat brain. It was found that the ester can be oxidized by the enzyme. Values of K(m) for SSA-Me were higher than for those for SSA, and for this substrate the enzyme showed a substrate- dependent inhibition. This finding suggests that the carboxylate group of SSA is not essential in the process of inhibition of SSADH by the substrate. Cyclopropyl analogues of SSA, cis- and trans-1-formyl-cyclopropan-2-carboxylic acids, were also individually tested as substrates of SSADH. Only the trans isomer was found to be oxidized to the corresponding dicarboxylic acid; it inhibited the enzyme in the same range of concentrations as SSA. The above data suggest that, as for γ-aminobutyric acid, SSA is present in an unfolded, transoid conformation at the active site of SSADH.Pubblicazioni consigliate
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