flwvm~. 77~. Vol 67. No. 2. pp. 283-322. 199.5 Copyright 0 1995 El\cvw Scimcc Ltd Pruned in Great Britain All nghts rcervcd 0163-7258195 $29.00 zyxwvutsr Pergamon 0163-7258(95)00019-4 Associare Editor: P. K. CHIANG ENGINEERING OF HUMAN CHOLINESTERASES EXPLAINS AND PREDICTS DIVERSE CONSEQUENCES OF ADMINISTRATION OF VARIOUS DRUGS AND POISONS MIKAEL SCHWARZ, DAVID GLICK, YAEL LOEWENSTEIN, and HERMONA SOREQ* Department of Biological Chemistry, The Institute of Life Sciences, The Hebrew University of Jerusalem, 91904 Israel Abstract -The acetylcholine hydrolyzing enzyme, acetylcholinesterase, primarily functions in nerve conduction, yet it appears in several guises, due to tissue-specific expression, alternative mRNA splicing and variable aggregation modes. The closely related enzyme, butyrylcholin- esterase, most likely serves as a scavenger of toxins to protect acetylcholine binding proteins. One or both of the cholinesterases probably also plays a non-catalytic role(s) as a surface element on cells to direct intercellular interactions. The two enzymes are subject to inhibition by a wide variety of synthetic (e.g., organophosphorus and carbamate insecticides) and natural (e.g., glycoalkaloids) anticholinesterases that can compromise these functions. Butyrylcholinesterase may function, as well, to degrade several drugs of interest, notably aspirin, cocaine and cocaine- like local anesthetics. The widespread occurrence of butyrylcholinesterase mutants with modified activity further complicates this picture, in ways that are only now being dissected through the use of site-directed mutagenesis and heterologous expression of recombinant cholinesterases. Keywords-Cholinesterase. alternative mRNA splicing, site-directed mutagenesis, organophosphorus, insecticide, anticholinesterase. I. 2. 3. CONTENTS Introduction Protein Chemistry and Enzymology 284 284 The Human Cholinesterase Genes 300 3.1. Structure of the gene 300 3.2. Chromosomal location 301 3.3. Control elements 301 3.4. Coordination of expression with other cholinergic factors 301 3.5. Alternative splicing 302 3.6. Polymorphism of molecular forms 302 *Corresponding author. Abbreviutions and nomenclature-ACh. acetylcholine; AChE, acetylcholinesterase enzyme; ACHE, acetylcholinesterase gene; AChR, acetylcholine receptor; AD, Alzheimer’s disease; ASG, active site gorge; ATCh, acetylthiocholine; BuChE, butyrylcholinesterase enzyme; BCHE, butyrylcholinesterase gene; BTCh, butyrylthiocholine; BW 284C51, 1,5-bis(4-allyldimethylammonium phenyl)pentan-3-l dibromide; CBS, choline- binding site; ChAT, choline acetyltransferase; ChE, cholinesterase enzyme; CUE, cholinesterase gene; DFP, diisopropylfluorophosphonate; Gl, G2, etc., monomeric, dimeric, etc., globular forms of a cholinesterase; GPI, glycophosphatidyl inositol; iso-OMPA. tetraisopropyl pyrophosphoramide; nAChR, nicotinic acetylcholine receptor; OP, organophosphates; 2-PAM, 2-pyridine aldoxime methiodide; PAS, peripheral anionic site; PD, Parkinson’s disease; THA. 1,2,3,4,-tetrahydro-9 aminoacridine (tacrine). For identification of amino acid residues, the sequence position in a particular ChE is given, followed in parentheses by the identity and position number of the homologous residue in Torpedo AChE. 283