Chemical messenger molecules, including hormones and neurotransmitters, mediate communication between adjacent and distant parts of all organisms. Many of these messengers are first produced in inactive precursor forms that requireactivation before they can exert their biological action on cells and tissues. Many precursor molecules give rise to more than one type of active messenger through this activation process. This study will examine what rules the organisms uses in the processing of these precursors. A model precursor molecule, proenkephalin, will be studied. The structure of proenkephalin will be modified using recombinant DNA technology to reveal what parts of the molecule are the usual sites for processing and what influences various structural features of the molecule have on processing. Also using this same technology, an attempt will be made to construct new types of precursors that will generate single active messengers without having to go through extensive procession. Such "minimal" precursors may be useful for delivery of specific hormones or neurotransmitters in gene therapy.
