Autoproteolysis of Procerain and Procerain B mediated by structural changes.

Procerain (Pc) and Procerain B (PcB) are two latex proteases from Calotropis procera having potential applications in food and other industries. However, autolytic degradation of these proteases limits their potential use in industry. Nevertheless, basic mechanism underlying the autoproteolysis has not been detailed. In order to understand the same, we subjected the enzymes to various denaturing and activating conditions. The results showed that structural changes induced by different denaturing conditions trigger their autoproteolysis. We also observed differential response of Pc, PcB and other papain-like proteases towards autocatalysis in presence of reducing agent in-spite of sharing the same structural fold, including the number of disulfide bonds. The possible reason underlying this intriguing observation is also discussed. Further, present work establishes that structural changes in the proteases lead to autoproteolysis and the enzymes are stable unless they experience structural perturbation. These findings could thus be useful for their practical applications in industries.

Is dexmedetomidine better than propofol and fentanyl combination in minor day care procedures? A prospective randomised double-blind study.

BACKGROUND AND AIMS: The growing popularity and trend of day care (ambulatory) anaesthesia has led to the development of newer and efficient drug regimen. We decided to evaluate the efficacy of two drug regimens namely dexmedetomidine and propofol with midazolam and fentanyl for moderate sedation characteristics in minor surgical procedures in terms of analgesia, intra-operative sedation, haemodynamic stability and side effects related. METHODS: Totally, 60 adult American Society of Anaesthesiologists class I-II patients posted for day care surgeries of duration <45 min divided into two groups; Group D, where dexmedetomidine loading dose at 1 µg/kg was administered over 10 min followed by maintenance infusion initiated at 0.6 µg/kg/h and titrated to achieve desired clinical effect with dose ranging from 0.2 to 0.7 µg/kg, Group P, where midazolam at 0.02 mg/kg and fentanyl at 2 µg/kg IV boluses were given followed by propofol infusion. Statistical analysis was done using student t-test, analysis of variance and Chi-square analysis. P < 0.05 was considered to be significant. RESULTS: Degree of sedation (Observer's Assessment of Activity and Sedation Scale ≤3) was comparable in both groups (P > 0.05). Rescue analgesia with fentanyl was needed in 30% patients of Group D compared to 17.63% patients of Group P (P < 0.05). The level of arousal was faster and better in Group D at 5 min after the procedure (P < 0.05). Haemodynamics were stable in Group D as with Group P patients (P < 0.005). Dry mouth reported by 16.67% patients. CONCLUSION: Dexmedetomidine can be a useful adjuvant rather than the sole sedative-analgesic agent during minor surgeries and be a valuable alternative to propofol in terms of moderate sedation, haemodynamic stability with minimal transient side effects.