SUBCELLULAR ANALYSIS OF MOLECULAR-FORMS OF ACETYLCHOLINESTERASE IN RAT SKELETAL-MUSCLE

Acetylcholinesterase (AChE, EC 3.1.1.7) activity of rat gastrocnemius muscle homogenized in 1 M‐NaCl and 0.5% Triton X‐100 was separated by velocity sedimentation in sucrose gradients into three molecular forms with sedimentation coefficients of about 4S, 10S and 16S. The distribution of homogenate AChE activity among the three peaks was 53, 34 and 13% respectively. The different molecular forms were found to be heterogeneously distributed in subcellular fractions prepared from sucrose homogenates of muscle, as follows: Subfractions of the crude sarcolemmal fraction were prepared by discontinuous sucrose gradient centrifugation. AChE was recovered in the greatest yield and with the highest specific activity in a light density subfraction (0.6/0.8 M‐sucrose interface). The AChE activity in this light density subfraction was mainly (81‐88%) the 10S form of the enzyme. The velocity sedimentation profiles of the AChE activity in the more dense subfractions were markedly different in that 16S AChE was a major component. Copyright © 1978, Wiley Blackwell. All rights reserved