INTRODUCTION

Papainase is a cysteine protease derived from Carica papaya and is commonly used in the food industry as a meat tenderizer.  In biotechnology, the enzyme is frequently used for the limited proteolysis of IgG to generate specific Fab and Fc fragments.  Medicinally, papainase has been used to liquify the contents of herniated vertebral discs so that their contents can be removed by aspiration [1], in wound debridement [2], and for the removal of dental caries [3] and exhibits antihelmintic properties [4].

High hydrostatic pressure (HPP) has been used for decades in the food industry for the inactivation of microbes and of the oxidases responsible for the browning of fruits and vegetables [5].  In biotechnology, HHP has been shown to accelerate the activity of proteases used for the digestion of proteins prior to mass spectrometry.  While the positive effects of temperature and pressure on the activity of several proteases are known [6,7], the potential synergy of elevated temperature with pressure has not been fully characterized, particularly in terms of real-time kinetic studies.  Using a high pressure optical cell coupled to a programmable high pressure generator, the effects of elevated pressure (0-60,000 psi) and temperature (22°C to 60°C) on the rate at which papainase digests a synthetic substrate was investigated.