The Core Facility provides equipment that allows UT Southwestern Medical Center investigators to make pre-steady state measurements of biochemical reactions on the 1-1000 ms time scale. The facility supports two BioLogic rapid-mixing devices that can be used for either optical stopped flow or quench flow experiments. Available stopped flow spectroscopy modes include absorbance, multi-wavelength absorbance, fluorescence (including multi-wavelength and polarization) and CD. Dead times approach 1 ms, minimum data acquisition time is about 1 ms, and minimal reagent volumes approach 20 microliters per shot. One mixer has thee syringes and another has four, all independently controlled by stepper motors. Mixers and spectroscopy components are computer controlled to allow for complex multi-stage mixing protocols.

The Core Facility provides no technical support. Each investigator is responsible for experimental design and execution. Control and data-acquisition software is provided along with software for data analysis. Investigators interested in using these facilities should first contact the director to discuss feasibility and to arrange training. Use is generally restricted to faculty members, post-doctoral researchers and advanced graduate students.

Cost: User fee is $100 per day or fraction thereof. Frequent users with NIH funding may join the users group, which replaces user fees with periodic assessments for maintenance costs, usually less than $1,000 per year. Priority for use is given to the user group, other NIH-funded investigators at UT Southwestern and then others. Accessibility is rarely a problem.