title: Human serum cholinesterase from liver pathological samples exhibit highly elevated aryl acylamidase activity.
abstract: BACKGROUND
  Although aspartate aminotransferase (AST) and gamma-glutamyltransferase (gamma GT) enzymes are widely used as markers for liver disorders, the ubiquitous enzyme butyrylcholinesterase (BChE), synthesized in liver is also used as marker in the assessment of liver pathophysiology. This BChE enzyme in addition to its esterase activity has yet another enzymatic function designated as aryl acylamidase (AAA) activity. It is determined in in vitro based on the hydrolysis of the synthetic substrate o-nitroacetanilide. In the present study, human serum cholinesterase (BChE) activity was studied with respect to its AAA activity on the BChE protein (AAA(BChE)) in patients with liver disorders. AST and gamma GT values were taken into account in this study as known markers for liver disorders.
  
  
  METHODS
  Blood samples were grouped into 3 based on esterase activity associated with BChE protein. They are normal, low, and very low BChE activity but with markedly increased AST and gamma GT levels. These samples were tested for their respective AAA function. Association of AAA with BChE from samples was proved using BChE monoclonal antibody precipitation experiment.
  
  
  RESULTS
  The absolute levels of AAA were increased as BChE activity decreased while deviating from normal samples and such deviation was directly proportional to the severity of the liver disorder. Differences between these groups became prominent after determining the ratios of AAA(BChE) to BChE activities. Samples showing very high AAA(BChE) to BChE ratio were also showing high to very high gamma GT values.
  
  
  CONCLUSIONS
  These findings establish AAA(BChE) as an independently regulated enzymatic activity on BChE especially in liver disorders. Moreover, since neither the low esterase activity of BChE by itself nor increased levels of AST/gamma GT are sufficient pathological indicators, this pilot study merits replication with large sample numbers.
authors: Department of Biotechnology, Bharathiar University, Coimbatore 641 046, Tamil Nadu, India. boopathybiotech@yahoo.com
authors: Rathanam
authors: R
authors: Boopathy
authors: Ramanna Valmiki
authors: RV
authors: Rajesh
authors: Sultan
authors: S
authors: Darvesh
authors: Paul G
authors: PG
authors: Layer
mesh_terms: D000581:Amidohydrolases / Q000097:blood*; D001219:Aspartate Aminotransferases / Q000097:blood; D002091:Butyrylcholinesterase / Q000097:blood* / Q000302:isolation & purification; D016022:Case-Control Studies; D004796:Clinical Enzyme Tests; D006801:Humans; D008099:Liver / Q000201:enzymology*; D008107:Liver Diseases / Q000097:blood / Q000201:enzymology*; D008110:Liver Extracts; D010865:Pilot Projects; D012680:Sensitivity and Specificity; D005723:gamma-Glutamyltransferase / Q000097:blood
chemical_list: D008110:Liver Extracts; D005723:gamma-Glutamyltransferase; D001219:Aspartate Aminotransferases; D002091:Butyrylcholinesterase; D000581:Amidohydrolases; C019732:aryl acylamidase