Table 1.
Summary of capabilities of calorimeters for measuring binding reactions. Ability to be used for indicated application is based on published data demonstrating measurement of the thermodynamic parameters indicated. Kd is the equilibrium dissociation constant, ΔH is the binding enthalpy, n is the stoichiometry coefficient, and ΔS is the binding entropy.
| Calorimeter | Configuration | Availability | Application | ||
|---|---|---|---|---|---|
| Thermodynamic characterization (Kd, ΔH, n, ΔS) | Screen by Kd | Screen by ΔH | |||
| iTC200 (Microcal) and Nano ITC Low Volume (TA Instruments) [14**,41–43] | ~200 μl chamber with stir paddle on spinning injection syringe Thermopile sensors (see online supplement for more detailed information) |
commercial instruments | Broad range of affinities: 20 μM < Kd < ~2 mM for low-C titrations (cannot determine n) 5 nM <Kd < 50 μM for direct titrations ~50 pM <Kd < 10 nM for competitive displacement titrations |
Low throughput (50/day max) | yes |
| Enthalpy array [26,27**,28*] | Open thermally isolated surface, 500 nl reaction, electrostatic drop merging, magnetic mixing Thermistor sensors |
research instrument | Limited range of affinities (Kd>10−5 M) | - | yes, higher throughput |
| [31] | Closed 10 μl chamber, 5 μl/min flow Thermopile sensors |
research instrument | - | - | One component immobilized |