ISOLATION AND PURIFICATION OF 3-MERCAPTOPYRUVATE SULFURTRANSFERASE FROM THE GUT OF RHINOCEROS LARVA (Oryctes rhinoceros)

ABSTRACT
Cyanide  is  known  to  be  one  of  the  most  toxic  substances present  in  a wide variety of food materials that are consumed by animals.
One  of  the  cyanide  detoxifying  enzymes  is  3-mercaptopyruvate sulfurtransferase  (3-MST).  Indeed,  recent  studies  have  clearly  shown  that  3-MST is involved in the detoxification of cyanide.
Rhinoceros (Oryctes rhinoceros) larva feeds on dead, decayed and living plants,  wood  and  palm.  Plants  are known  to  contain  cyanide  as  a  defence mechanism  for  intruding/pesting  organisms. Thus,  for rhinoceros larva  to  be able to live on plants, it must have possessed a cyanide-detoxifying enzyme.
3-MST,  a  cyanide-detoxifying  enzyme  was  purified  from Rhinoceros (Oryctes rhinoceros) larva in this work.
The 3-MST enzyme was isolated from the gut of Oryctes rhinoceros larvae and purified using Ammonium Sulphate Precipitation, Bio-Gel-P-100 Gel Filtration Chromatography and Reactive Blue-2-Agarose Affinity chromatography.
The specific activity of the enzyme was 0.22U/mg.
The presence of this enzyme could be exploited by including it in the diet of animals which  would serve  as a source  of  protein  and  3-MST. Perhaps,  these rhinoceros larva could be introduced on farmland with contaminated soil whereby they will process the dead roots and plants into soil thereby providing more space and manure for plants to grow healthy. 

CHAPTER ONE

INTRODUCTION
    One of the major metabolic enzymes that have gained so much interest of scientists is 3-Mercaptopyruvate sulfurtransferase (3-MST). This enzyme occurs widely in nature (Bordo, 2002 and Jarabak, 1981).
It  has  been  reported  in  several  organisms  ranging  from humans  to  rats,fishes and insects. It is a mitochondrial enzyme which has been concerned in the detoxification of cyanide, a potent toxin of the mitochondrial respiratory chain (Nelson et  al.,  2000).  Among  the  several  metabolic  enzymes  that  carry  out xenobiotic  detoxification,  3-mercaptopyruvate  sulfurtransferase  is  of  utmost importance.
3-mercaptopyruvate  sulfurtransferase functions  in  the  detoxifications  of cyanide; mediation of sulfur ion transfer to cyanide or to other thiol compounds.(Vanden et al., 1967). It is also required for the biosynthesis of thiosulfate. In combination with cysteine aminotransferase, it contributes to the catabolism of cysteine and it is important in generating hydrogen sulphide in the brain, retina and vascular endothelial cells (Shibuya et al., 2009). It also acquired different functions  such  as  a  redox  regulation  (maintenance  of  cellular  redox homeostasis)  and  defense against  oxidative  stress,  in  the  atmosphere  under oxidizing conditions Nagahara et al (2005).
Hydrogen sulphide  (H2S)  is  an  important  synaptic  modulator,  signalling molecule, smooth muscle contractor and neuroprotectant (Hosoki et al., 1997).
Its  production  by  the  3-mercaptopyruvate  sulfurtransferase  and  cysteine aminotransferase pathways is regulated by calcium ions (Hosoki et al., 1997).
      Organisms  that  are  exposed  to  cyanide  poisoning  usually  have  this enzyme  in  them.  This  could  be  in  food as  in  the  cyanogenic glucosides being consumed. It has been studied from variety of sources, which include bacteria,yeasts, plants, and animals (Marcus Wischik, 1998). 
Cyanide could be released into the bark of trees as a defence mechanism.
There are array of defensive compounds that make their parts (leaves, flowers, stems,  roots  and  fruits)  distasteful  or  poisonous  to  predators.  In  response,

however,  the  animals  that  feed  on  them  have  evolved  over  successive generations a range of measures to overcome these compounds and can eat the plant  safely.  The  tree  trunk  offers  a  clear  example  of  the  variety  of  defences available to plants (Marcus Wischik, 1998).

Oryctes rhinoceros larva is one of the organisms that are also exposed to cyanide toxicity because of the environment they are found.