The effects of PMSF and cysteine addition into partially purified bromelain from pineapple (Ananas comosus [L] Merr) cores to its kinetics behaviour

Abstract

Bromelain found in various tissues in the pineapple plant (Ananas Comusus [L] Merr. The bromelain will be taken from pineapple cores for kinetic study. The effect of addition organic compounds, such as phenylmethylsulfonyl fluoride (PMSF) and cysteine on its kinetics behaviour will be determined by proteolytic activities of the bromelain. The stages of this study were started from isolation of crude enzyme, fractionation with ammonium sulphate salt, dialysis, and ion-exchange column chromatography with CM sephadex C-50 for enzyme purification. The obtained enzyme fractions from crude enzyme, ammonium sulphate, dialysis, and CM-sephadex C-50 ion exchange chromatography have specific activities of 45.39, 238.31, 311.16, and 427.13 U/mg, respectively. The purification stages result in increasing of the bromelain specific activities by 9 times compared to the crude enzyme. The Michaelis-Menten constant (Km) value for the purified bromelain was 0.85 % casein and the Vmax value was 0.41 U/min. Addition of PMSF and cysteine compound effect on its Vmax and Km with various trends. The Vmax value will be decreased by addition of PMSF and increased by addition of cysteine. Thus, proteolytic activity of bromelain from pineapple cores can be significantly increased by the addition of cysteine compounds and inhibited by the addition of PMSF.