The Mechanism for the Synthesis of Starch and Its Relationship to the Newly Proposed Structural Model for DNA. Part I.

The physical and chemical properties of starch and glycogen can be explained on the basis that glycogen is converted into amylose and amylopectin by a debranching enzyme (isoamylase) which removes the external α‐1,6‐linked branches of the glycogen. This precursor glycogen exists in all corn endosperm examined: ae high amylose, normal dent, waxy, and sweet corn. Analyses of amylopectins show that they behave as statistical condensation polymers (the model‐V of Erlander and French) which have been debranched. Further support for the mechanism is given by the fact that the chain length and degree of branching of the interior part of all amylopectins is essentially the same as that of its precursor glycogen. Any mechanism for starch synthesis must, however, consider the complexing of enzymes because both amylopectin and glycogen behave as if they were strongly complexed to proteins. Thus proteases can destroy these complexes and viscosity differences of various barley geneotype starches can be correlated to protein content. Acid hydrolysis studies on corn amylopectins suggest that the type of protein complexed with amylopectin changes with both endosperm maturity and corn variety. Amylose synthesis from debranched chains can be correlated with the ability of chromosomes to regulate when and in what sequence an enzyme is synthesized. The proposed model for desoxyribonucleic acid (DNA) – which is a hollow cylinder with the bases on the outside – can explain how these regulators (genetic repressors and inducers) can function. „Proofs” for the Watson‐Crick model such as X‐ray analyses, hypochromism, and molecular dimensions are shown to be erroneous.