Isolation and characterization of a cDNA clone from Lolium temulentum L. encoding for a sucrose hydrolytic enzyme which shows alkaline/neutral invertase activity |
| |
Authors: | Gallagher J; Pollock C |
| |
Institution: | Institute of Grassland and Environmental Research, Plas Gogerddan, Aberystwyth, Ceredigion SY23 3EB, UK; Corresponding author; e-mail: joe.gallagher@bbsrc.ac.uk |
| |
Abstract: | A novel cDNA clone, functionally expressed in E. coli,
was isolated from a L. temulentum L. cDNA library. The
expressed protein hydrolysed sucrose with an apparent
Km of approximately 18 mM, and produced equi-molar
concentrations of glucose and fructose. Optimum activity was observed at pH
7-7.5; there was little or no activity at pH 5.5. The expressed protein did
not hydrolyse raffinose, stachyose or maltose. The activity of the
expressed protein was inhibited by fructose (50% at 15 mM) and TRIS (50% at
2.5 mM), but was not affected by MgCl2, CaCl2 or MnCl2. These findings
suggest that this cDNA clone encodes for an alkaline/neutral invertase.
Sequence analysis revealed little homology with published sequences for
acid invertase, however the invertase motif (NDPN) identified in other
invertases was present. Expression studies show that the gene encoding for
this enzyme is not regulated by sucrose accumulation in leaf
tissue. |
| |
Keywords: | |
本文献已被 Oxford 等数据库收录! |
|