PROPERTIES OF A PROTEIN ANTIGENICALLY RELATED TO TRYPTOPHAN SYNTHETASE INNEUROSPORA CRASSA

Abstract

Rabbit antibody against partially purified preparations of Neurospora crassa tryptophan synthetase (Tsase) quantitatively and completely neutralizes enzyme activity, and the neutralization reaction is unaffected by substrate or pyridoxal phosphate. A mutant unable to convert indole to tryptophan and lacking Tsase produces a protein (CRM) immunologically indistinguishable from the enzyme. Tsase and CRM can be distinguished by their different stability on dialysis. Quantitative neutralization, adsorption and precipitin studies indicate that the Tsase-anti-Tsase and CRM-anti-CRM reactions can be studied as single antigen-antibody systems, so as to permit detailed immunochemical analysis of the problem of gene function and enzyme formation.