Enzymes starch-metabolizing

Huber, W., de Fekete, A., and Ziegler, H. 1969. Enzymes of starch metabolism in chloroplasts of the bundle sheath and palisade cells of Zea mays. Planta 87, 360-364. 

Spilatro, S. R., and Preiss, J. 1987. Regulation of starch synthesis in the bundle sheath and mesophyll of Zea mays L. Intercellular compartmentalization of enzymes of starch metabolism and the properties of the ADPglucose Pyrophosphorylases. Plant Physiol. 83, 621-627. 

More investigations of the molecular size of starch-metabolizing enzymes are required. 

A study of enzyme kinetics is extremely important, as it often gives information about the mechanism of action of the enzyme concerned. We shall therefore outline some of the theories of enzyme kinetics that have been applied to starch-metabolizing enzymes. 

Wrinkled pea has a reduced starch level 66-75% of that seen in the normal round seed. The amylose content is about 33% in the wild-type round form, but is 60—70% in the wrinkled pea seed. Edwards et measured several enzyme activities involved in starch metabolism at four different developmental stages of wrinkled pea and found that branching enzyme activity at its highest level was only 14% of that observed for... 

A C. reinhardtii mutant lacking D-enzyme activity has been characterized and has been shown to have significantly lower levels of starch. Other enzymes involved in starch metabolism such as ADP-Glc PPase, granule-bound and soluble starch synthase, BE, phosphorylase, a-glucosidase, amylases, and debranching enzyme activities were not affected. The starch content in the mutant was about 6-13% of wild type and there was an excessive accumulation of maltooligosaccharides up to a polymer size of 16 glucose units. 

Thorpe, T.A. and D.D. Meir Enzymes of starch metabolism in Nicotiana tabacum callus Phytochemistry 13 (1974) 1329-1334. 

---