Molecular cloning and gene expression analysis of tomato endo-beta-N-acetylglucosaminidase, an endoglycosidase involved in the production of high-mannose type free N-glycans during tomato fruit ripening.

In this study, we identified a gene encoding tomato ENGase (Endo-LE) using the gene information of rice ENGase, and expressed the Endo-LE protein in Escherichia coli. The substrate specificity of the recombinant Endo-LE was the same as that of the native enzyme, showing strong activity towards the high-mannose type N-glycans with the Manalpha1-2Manalpha1-3Manbeta1-4GlcNAcbeta1-4GlcNAc unit. Real-time PCR analysis revealed that the gene expression of Endo-LE did not vary significantly with the tomato ripening process, indicating that Endo-LE activity is ubiquitously expressed.