Journal
JOURNAL OF PLANT PHYSIOLOGY
Volume 160, Issue 8, Pages 851-857Publisher
URBAN & FISCHER VERLAG
DOI: 10.1078/0176-1617-01105
Keywords
Zea mays; bundle sheath; glycolate oxidase; glycolate pathway; mesophyll; photorespiration
Categories
Ask authors/readers for more resources
Glycolate oxicase (EC 1.1.3.15) activity was detected both in the bundle sheath (79%) and mesophyll (21 %) tissues of maize leaves. Three peaks of glycolate oxidase activity were separated from maize leaves by the linear KCl gradient elution from the DEAE-Toyopearl column. The first peak corresponded to the glycolate oxidase isoenzyme located in the bundle sheath cells, the second peak had a dual location and the third peak was related to the mesophyll fraction. The mesophyll isoenzyme showed higher affinity for glycolate (K-m 23 mumol . L-1) and a higher pH optimum (7.5-7.6) as compared to the bundle sheath isoenzyme (K-m 65 mumol . L-1, pH optimum 7.3). The bundle sheath isoenzyme was strongly activated by isocitrate and by succinate while the mesophyll isoenzyme was activated by isocitrate only slightly and was inhibited by succinate. It is concluded that although the glycolate oxidase activity is mainly attributed to the bundle sheath, conversion of glycolate to glyoxylate occurs also in the mesophyll tissue of C-4 plant leaves.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available