Starch-branching enzyme

The first enzymic studies done on the dul mutant were carried out in 1981, and both SSII and starch-branching enzyme Ha (SBEIIa) were found to have reduced activity in the endosperm compared to normal maize endosperm.204 SSII was shown to be different from SSI.173,205 SSII requires a primer for activity, and could not catalyze an unprimed reaction even in the presence of 0.5 M citrate, it also has less affinity for amylopectin than does SSI. However, 0.5 M citrate lowered the Km for amylopectin 17-fold. The activity with glycogen as a primer is one-half that observed with amylopectin. Therefore, glycogen is not as effective as a primer as is amylopectin, which differs from what was observed for starch synthase I. Both maize endosperm SSI and SSII had a Km for ADPGlc of 0.1 mM.196,205... 

Singh and Preiss265 concluded that, although some homology exists between the three starch-branching enzymes, there are major differences in the structure of BEI when compared to BEIIa and BEIIb, as shown by its different reactivity with some monoclonal antibodies and differences in amino acid composition and proteolytic digest maps. 

Primary, secondary and tertiary structures of amylolytic enzymes from a wide variety of sources and functions (the a-amylases, bacterial cyclomaltodextrin glucanosyltrans-ferases, isoamylases and starch-branching enzymes) have been found to be closely related, and have been placed into the so-called structural a-amylase family.176,177 These enzymes have been studied with regard to the number, structure, organization and function of domains.178... 

Bhattacharyya, M. K., Smith, A. M., Noel-Ellis, T. H., Hedley, C., and Martin, C. 1990. The wrinkled-seed character of pea described by Mendel is caused by a transposon-like insertion in a gene encoding starch-branching enzyme. Cell 60, 115-122. 

Boyer, C. D and Preiss, J. 1978b. Multiple forms of starch branching enzyme of maize Evidence for independent genetic control. Biochem. Biophys. Res. Commun. 80,169-175. 

Denyer, K., Sidebottom, C., Hylton, C. M., and Smith, A. M. 1993. Soluble isoforms of starch synthase and starch-branching enzyme also occur within starch granules in developing pea embryos. Plant J. 4,191-196. 

Fisher, D. K., Boyer, C. D., and Hannah, L. C. 1993. Starch branching enzyme II from maize endosperm. Plant Physiol. 102, 1053-1054. 

Fisher, M. B., and Boyer, C. D. 1983. Immunological characterization of starch branching enzymes. Plant Physiol. 72, 813-816. 

Goldner, W., and Beevers, H. 1989. Starch synthase and starch branching enzyme from germinating castor bean endosperm. Phytochemistry 28, 1809-1812. 

Khoshnoodi, J., Ek, B., Rask, L., and Larsson, H. 1993. Characterization of the 97 and 103-KDa forms of starch branching enzymes from potato tubers. FEBS Lett. 332,132-138. 

Mizuno, K., Kawasaki, T., Shimada, H., Satoh, H., Kobayashi, E., Okamura, S., Arai, Y., and Baba, T. 1993. Alteration of the structural properties of starch components by the lack of an isoform of starch branching enzyme in rice seeds. J. BioL Chem. 268,19084-19091. Mizuno, K., Kimura, K., Arai, Y., Kawasaki, T., Shimada, H., and Baba, T. 1992. Starch branching enzymes from immature rice seeds. /. Biochem. 112, 643-651. 

Singh. B. K., and Preiss, J. 1985. Starch branching enzymes from maize Immunological characterization using polyclonal and monoclonal antibodies. Plant Physiol 79, 34-40. 

Smith, A. M. 1988. Major differences in isoforms of starch-branching enzyme between developing embryos of round and wrinkled-seeded peas (Pisum sativum L.). Planta 175,270-279. 

Smyth, D. A. 1988. Some properties of starch branching enzyme from indica rice endosperm (Oryza sativa L.). Plant Sci. 57, 1-8. 

Vos-Scheperkeuter, G. H., de Wit, J. G., Ponstein, A. S., Feenstra, W. J., and Witholt, B. 1989. Immunological comparison of the starch branching enzymes from potato tubers and maize kernels. Plant Physiol 90,75-84. 

Yamanouchi, H., and Nakamura, Y. 1992. Organ specificity of isoforms of starch branching enzymes (Q-enzyme) in rice. Plant Cell Physiol. 33, 981-985. 

Branching isoenzymes from rice (21, 133), wheat (134, 135), and barley (136, 137) have also been characterized. The effects on starch structure in plants that have mutations in the starch-branching enzymes have been reviewed (2-4, 118, 124). 

Starch branching enzyme from immature rice seeds. J. Biochem. 1992 112 643-651. 39. 

Khoshnoodi J, Blennow A, Ek B, Rask L, Larsson H. The multiple forms of starch-branching enzyme in Solanum tuberosum. Eur. J. Biochem. 1996 242 148-155. 

Jobling SA, Schwall GP, Westcott RJ, Sidebottom CM, Debet M, Gidley MJ, Jeffcoat R, Safford R. A minor form of starch branching enzyme in potato (Solanum tuberosum L.) tubers has a major effect on starch structure cloning and characterisation of multiple forms of SBEA. Plant J. 1999 18 163-171. 

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