Properties and Classification of the Soluble Esterases of Human Brain

Abstract

I%iater-soluble proteins and enzymes of human brain were separated by vertical zone electrophoresis in starch gel. Fifteen bands of esterase activity were detected in brain. Various substrates and inhibitors were used in efforts to identify enzymes in addition to a comparison caf the esteras pattern with patterns obtained from other human tissues. 0116 zone, conaposed of four bands of acetylesterase activity, was found to be conlmon t o all the tissues investigated with the exceptioi~ of serum. ' H' wo bands of choliriesterase and two bards of A-esterase activity were identified. The remaitring bands, which were aliesterases possessirig broad overlapping substrate specificity and inhibitor sensitivity, were eiectrophsretically differerat from thsse of other tissues. Observatio~~s on alkaline phosphatase, acid phosphataue, and lactate dehydrogenase were recorded for conaparison with the data an esterases.The colxaplexity of the esterase activity of Inlaman brain has been investigated with techniques s f differential inhibition and substrate specificity (1-5). The esterases which have been identified include aeetylcholinesterase (1,4), butyryleholinesterase (2,4), a Ca++-dependent arylesterase (A-esterase) ( 3 ) , arad nonspecific esterases which hydrolyze phenyl acetate and phenyl butyrate (3).Several publicatio~~s have described the electrophoretic separation of specific and nonspecific brain esterases in various supporting media (6-8). A paper recently published by Barrsn et ak. (9) was nf particular interest because the brain esterases showed electrophoretic patterns sirni%ar to those observed in this labsratesrg-; for esterases separated from extracts of other human tissues (10-13). The present investigations evere carried out t s compare the electrophoretically separated esterases of human brain with thsse observed by sther workers and to correlate these enzgrnles with those found in other tissues sf the human Isody. MethodsSamples from different-regions of the human brain were obtained at autopsy and were frozen immediately upon removal. The tissue was either used a t once s r stored a t -20 "C until just before use. Hamogenatea of white and gray ~natter (separate or mixed) were prepared in distilled water in a 1:2 dilution (grams wet tissue per milliliter water) with a DuaEI homogenizer maintained at approximately 4 "C in a bath sf ice water. The hamogenates were frozen and thawed several times and were then centrifuged in a refrigerated centrifuge a t 35,000 g for 7 ' 5 minutes. The supernatants \%yere removed by pipette, placed

Genetics of Esterases in Man

“…Extensive studies have been made of classification and comparison of esterases in tissue homogenates of man (Paul & Fottrell, 1961;Blanco & Zinkham, 1966: Ecobichon & Kalow, 1961, 1962Ecobichon, 1966). Esterases in these studies were characterized by their substrate specificities and inhibition properties.…”