Branching enzyme genetic studies

Genetic Studies on Branching Enzyme-Deficient Mutants... 

Conversely, a large body of evidence strongly indicates that the main, if not the only, pathway of starch synthesis consists of the enzymatic reactions catalyzed respectively by ADPGlc PPase (reaction 3a), the starch synthase reaction (reaction 2), and the branching enzyme (reaction 5). The data supporting this view are from a number of biochemical and genetic studies. 

Reactions in which aspartate functions as a nitrogen donor have not been studied in the detail that reactions involving glutamine have. The important role of adenylosuccinate synthetase at a branch point of purine metabolism and as a component of the purine nucleotide cycle makes this enzyme a challenging subject for study. This article will deal with regulatory, kinetic, and genetic aspects of adenylosuccinate synthetase from a variety of systems. 

Interest in the genetic engineering of both plants and micro-organisms for the production of tailor made amylose, amylopectin and/or starches has also been reported. Furthermore, investigations on the enzymatic modification of starch and its major components, for example the introduction of additional branches composed of glucose and/or other monosaccharides and/or uronic acids as well as amino acids or peptides, to produce carbohydrates of possibly comparable functionality to galactomannans, pectin, gum arable, etc., has been initiated. Also studies on the metabolic fate of carbohydrates in food, the biosynthesis of starch, the fine structure of starch from different sources, the effect of electrolytes on the gelatinization of starch and the development of enzymic methods for starch analyses are still active. 

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