Funds are requested for the acquisition of a stopped-flow spectrometer for absorbance, circular dichroism and fluorescence measurements. Projects will be conducted by six major users from the Departments of Physiology & Biophysics and Chemistry. The instrument will be used in investigations of protein folding, enzyme mechanisms, peptide and protein interactions with membranes. Prof. McLaughlin will study the interactions of the proteins Src and MARCKS with membranes. Prof. Miller will study the folding and assembly of multidomain proteins. Prof. Raleigh will use this instrumentation to help elucidate the folding pathway of two proteins. Prof. Sampson will study the mechanism of the important enzyme cholesterol oxidase. Prof. Scarlata will investigate the activation of phospholipase C by G proteins. Prof. Wishina will study the dynamics of molten globule states of proteins. The instrument will be housed in a shared instrumentation laboratory located in the Chemistry Department and operated as a user-accessible, operator maintained shared facility.