Anomalous transitions of DODAB using fast scanning liquid calorimetry

Anomalous melting transitions are observed on dimethyl dioctadecyl ammonium bromide (DODAB) using a fast-scanning liquid calorimeter. A single transition is observed at low scan rates (1 K/min) while up to four peaks are evident at high scan rates (60 K/min). These deconvoluted transitions are signatures of the basic properties of the transition kinetic landscape which are convoluted into a single peak at low scanning rates. The technique is also applied to the proteins Rnase A, Lysozyme and Cytochrome P450. The calorimeter is a glass capillary uniformly coated with Ag, which acts both as the heating element and resistive thermometer.

► A capillary based liquid calorimeter with fast heating rate is developed.
► Multiple peaks in DODAB melting transition is observed at high heating rates.
► The calorimeter is used for protein unfolding phase transition.