Note. The industrial utilization of pectin methylesterase inhibitor is patent pending It. no. 47961-A89.
A glycoprotein inhibitor of pectin methylesterase in kiwi fruit (Actinidia chinensis)
Article first published online: 3 MAR 2005
European Journal of Biochemistry
Volume 193, Issue 1, pages 183–187, October 1990
How to Cite
BALESTRIERI, C., CASTALDO, D., GIOVANE, A., QUAGLIUOLO, L. and SERVILLO, L. (1990), A glycoprotein inhibitor of pectin methylesterase in kiwi fruit (Actinidia chinensis). European Journal of Biochemistry, 193: 183–187. doi: 10.1111/j.1432-1033.1990.tb19321.x
- Issue published online: 3 MAR 2005
- Article first published online: 3 MAR 2005
- (Received February 12, 1990) – EJB 90 0153
The finding of a powerful inhibitor of pectin methylesterase in ripe kiwi fruit is reported. The inhibitor was revealed to be a glycoprotein. It was purified to homogeneity and found to have a molecular mass of about 28 kDa, as estimated by gel filtration chromatography, SDS/PAGE and analytical ultracentrifugation. The sugar portion is composed of galactose, arabinose and rhamnose, the latter being much less represented. The amino acid composition showed a very high content of acidic residues compared to basic ones, which is the reason for the very low isoelectric point of the protein (less than 3.5). The kind of inhibition on kiwi pectin methylesterase was found to be competitive with an apparent Ki of 0.22 μM, using citrus pectin as a substrate. Moreover, the inhibitor is effective in inhibiting pectin methylesterase in the pH range 3.5–7.5. Kiwi inhibitor appears to be specific for pectin methylesterase, inasmuch as it was found to be ineffective against other polysaccharide-degrading enzymes, such as polygalacturonase and amylase. Conversely, it appears to be completely aspecific as far as the pectin methylesterase source is concerned. In fact, it was found to inhibit this enzyme effectively from all the sources we assayed, i. e. orange, tomato, apple, banana, potato.
pectin methylesterase inhibitor
Pectin methylesterase (EC 126.96.36.199)
polygalacturonase (EC 188.8.131.52)
α-amylase (EC 184.108.40.206)