Acetylcholinesterase Inactivation of Enzymetreated Erythrocytes

Loss of Acetylcholinesterase Activity in Human Erythrocytes Treated with Cephalothin

“…The failure to restore enzyme activity by repeated washing of the antibiotic-treated cells indicated that the effect was irreversible, thereby resembling the inactivating action observed with benzylpenicillin [10]. The present findings are also reminiscent of the effects of proteases [7] and of tannic acid [20] on erythrocyte enzymes; that is, only the membrane associated ACHE, but not the intracellularly located G6PD was destroyed when whole red cells were exposed to the antibiotic. These observations suggest that cephalothin only interacts with specific segments of the outer surface of the human erythrocyte.…”

“…However, studies with red cells separated in accordance with their density revealed that in this disorder the enzyme distribution pattern was characteristically different than that found in ABO hemolytic disease [6]. Investigations undertaken to elucidate the pathophysiology of this enzyme defect have shown that alterations of ACHE activity can be produced by exposing normal erythrocytes to certain chemically-unrelated sub stances which interact with the red cell membrane [7][8][9]. From in activation studies with proteolytic enzymes it has been inferred that ACHE appears to be located at the outer surface of the human erythrocyte [5].…”

“…For comparison, red cells were also exposed to two analogues of cephalo thin: cephaloridine [7-(2-thienyl acetamido)-3-(l-pyridylmethyl)-3-cephem-4-carboxylic acid betaine] and cephaloglycin [7-(D-a-aminophcnylacctamide) cephalosporanic acid zwitterion]. Glucose-6-phosphate dehydrogenase (G6PD) was used as a marker to assess an effect on intracellularly located enzymes [7]. While this work was in pro gress, S ir c h ia et al [18] reported that cephalothin at a concentration of 40 mg/ml converted normal erythrocytes into PNH-like cells: i .e.…”

Differences between the Red Cell Acetylcholinesterase Defects of Paroxysmal Nocturnal Hemoglobinuria and of ABO Hemolytic Disease

“…A similar enzyme defect has been detected in red cells of patients with paroxysmal nocturnal hemo globinuria (PNH) (2,3). Alterations of ACHE activity can also be produced artificially by treating normal erythrocytes with proteo lytic enzymes (4,5) and with certain sulfhydryl reagents (6).…”

A Review: Human Erythrocyte Acetylcholinesterase

“…However, an exception is seen in pa- Brauer and Root [11] in 1945 showed that after in vitro hemolysis, acetylcholinesterase activity can be recovered in the erythrocyte membrane. Studies with proteolytic enzymes, which are unable to traverse the erythrocyte membrane, have indicated that acetylcholinesterase or its active sites are located at or near the outer surface of the human erythrocyte [7,30,51,74]. It has been suggested on the basis of a molecular weight of 90,000 or 180,000/active site that 0.2% of human erythrocyte membrane proteins is active acetylcholinesterase [6].…”