Multiple forms of rat liver L-asparagine synthetase

Extraction of rat liver asparagine synthetase from rats maintained on normal protein containing diets yields activity in a region corresponding to a molecular weight of 57,000. Decreasing the amount of protein in the diets caused the asparagine synthetase activity to appear in two forms, one being in the 57,000 region and the other in the 113,000 region. If rat were fed a high protein diet, liver asparagine synthetase activity appeared only in the lower molecular weight area. Experiments with synthetic amino acid diets demonstrated that a dietary deficiency in asparagine would cause the appearance of high molecular weight (113,000) hepatic asparagine synthetase.