The objective of this study was to investigate the response of sarcoplasmic proteins in bovine longissimus muscle to low-voltage electrical stimulation (ES, 80 V, 35 s) after dressing and its contribution to meat tenderization at early postmortem time. Proteome analysis showed that ES resulted in lower (P <0.05) phosphorylation levels of creatine kinase M chain, fructose bisphosphate aldolase C-A, ß-enolase and pyruvate kinase at 3 h postmortem. Zymography indicated an earlier (P <0.05) activation of µ-calpain in ES muscles. Free lysosomal cathepsin B&L activity increased faster (P <0.05) in ES muscles up to 24 h. Immunohistochemistry and transmission electron microscopy further indicated that lysosomal enzymes were released at early postmortem time. ES also induced ultrastructural disruption of sarcomeres. In addition, ES accelerated (P <0.05) depletion of ATP, phosphate creatine and glycogen, as well as pH decline and more preferred pH/temperature decline mode. Finally, ES accelerated meat tenderization with lower (P <0.05) shear force values than control over testing time. A possible relationship was suggested between change in phosphorylation level of energy metabolic enzymes and postmortem tenderization of beef. Our results suggested the possible importance of activation of µ-calpain, phosphorylation of sarcoplasmic proteins and release of lysosomal enzymes for ES-induced tenderization of beef muscle.