Acid invertase

Cell wall properties of transgenic tobacco plants that express a yeast derived acid invertase in their vacuole... 

Acid invertase and UDP-glucose phosphoiylase appear to be especially important components of the carbohydrate metabolism pathway as it relates to the accumulation of reducing sugars. Alleles associated with both enz5mies have been found to be associated with resistance to cold sweetening (Sowokinos et al., 1997 Sowokinos, 2001 Li et al., 2005 McKenzie et al., 2005). 

McKenzie, M. J., Sowokinos, J. R., Shea, I. M., Gupta, S. K., Lindlauf, R. R., Anderson, J. A. D. (2005). Investigations on the role of acid invertase and UDR-glucose phyrophosphorylase in potato clones with varying resistance to cold-induced sweetening. American Journal of Potato Research, 82, 231-239. 

Kim, H. Y., and Suzuki, Y. (1989). Changes in assimilated BC distribution and soluble acid invertase activity of Zinnia elegans induced by Uniconazol an inhibitor of gibberellin biosynthesis. Plant Physiol. 90, 316-321. 

Table III Effect of SSHB on sugar-beet total biomass and leaf acid invertase activity...

Conditions see Table II Assay Procedures The activity of acid invertase (free and bound) was determined in plant material that was frozen in liquid nitrogen, freeze-dried, pulverized, homogenized with mercaptoethanol, centrifuged at 25,000g for 30 min (4WC) solution and residue were dialyzed (48 h, 4WC) and then incubated with sucrose (pH 4.7, 1 h, 30 0 and glucose was analyzed electrochemically. 

Treatment (dose in mg/ha) Total Dry Mass Activity of Acid Invertase in g/vessel in /umol sucrose hydrolyzed 100 mg dry mass h Young Leaves Old Leaves ... 

Effects of brassinosteroids on the activity of acid invertases in leaves. The first question to be answered was why does SSHB increase the total biomass under mild stress conditions It is known that rate of cell growth correlates with specific activity of acid invertase (4) and the role of acid invertase in the leaves of sugar-beet plants has been described (5). Table III shows total mass (from Table II) in relation to the activity of acid invertases. 

The next question to be considered was what relation exists between the total biomass of plants and the activity of acid invertases in young leaves It seemed possible that this question could be answered by measuring these parameters shortly after homobrassinolide application. The results of experiments with young plants are given in Table IV. 

The data show that SSHB increased the root dry matter in the same way it did in the other experiments. Simultaneously, we observed an increase in leaf length and leaf area which corresponded with an increase in invertase activity. The higher enzyme activity appeared to be the key to the whole problem. It is well known that acid invertase splits the disaccharide sucrose so that the two monosaccharides formed from it can become building stones for additional leaf substances. That is, glucose is recycled through the Embden-Meyerhof-Parnas pathway. Likewise, fructose is readily available for conversion into fructose 1,6-diphosphate. Subsequently, more leaf area arises which is able to produce more assimilates. The consequence is an increased yield. Thus, photosynthetic efficiency increases considerably. 

Effects of brassinosteroids on the activity of acid invertase in tap-root. The next question to be considered was whether such a relationship may also be valid for increases in the amount of tap-root dry matter after application of SSHB. Table V shows these data for the roots. There is a close correlation between increases in root dry matter and the activity in acid invertase after application of SSHB. This may be... 

Table IV. Effect of SSHB on sugar-beet growth and acid invertase measured a short time after application...

Treatment Dry Mass Length Activity of Acid Invertase of Leaves... 

Conditions see Table II Assay Procedures Activity of acid invertase, see Table III conducted at harvest time Activity of sucrose synthase - conducted at harvest time on freeze-dried plant material that was mixed with the extraction solvent bull serum albumin and buffer (HEPES, EDTA, dithiothreite, pH 7.5 at 4 C), incubated with fructose and i4C UDP glucose (1 h, 30 °C), separated via thin layer chromatography and the 14c sucrose assayed by scanning, r = correlation coefficient... 

Zhu, Y.J., Komor, E., and Morre, P.H., Sucrose accumulation in the sugarcane stem is regulated by the difference between the activities of soluble acid invertase and sucrose phosphate synthase. Plant Physiol., 115, 609, 1997. 

Invatex DTPA-41. See Pentetic acid Invatex EDTA-30. See Edetic acid Invertase... 

More recently Maignan has described the preparation of a range of insoluble humic acid - invertase - Ca complexes. By varying the concentration and order of addition of reactants, as well as the time of incubation of the organic components with Ca, preparations were obtained which differed in their initial specific activities and their stabilities on repeated incubation with substrate. When complexes were formed by adding invertase to suspensions of insoluble Ca-humate, the invertase was bound by adsorption at the surface of the support. When the enzyme was mixed with the soluble neutralized humic acid before Ca addition, the invertase was partly adsorbed to surfaces, possibly involving covalent bond formation, and partly entrapped within micelles. 

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