Multiple sequence alignment of the three conserved hydrophobic residues (shown in bold) of some cell wall invertases: Arabidopsis cell wall invertase 1, S. tuberosum cell wall invertase 1, N. tabacum cell wall invertase, S. tuberosum cell wall invertase 2, S. tuberosum cell wall invertase 3, V. faba cell wall invertase, P. sativum cell wall invertase, V. faba cell wall invertase 2, O. sativa cell wall invertase, wheat cell wall invertase, Z. mays cell wall invertase 3, Z. mays cell wall invertase 1, and Z. mays cell wall invertase 2.