Extractability of glycolytic enzymes from the ordinary muscle of red sea bream. Pacific mackerel and carp was examined in a range of 0-0.3_M KCl (pH 6.8-7.1). The amount of extracted proteins increased w ?? th an increase of KCl concentration up to 0.1M, irrespective of fish species. The dependency on KCl concentration of the extractability of glycolytic enzymes such as aldolase (ALD), glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and glucosephosphate isomerase (GPI) was roughly comparable to that of total sarcoplasmic proteins. Sarcoplasmic proteins, as well as ALD, GAPDH and GPI, of Pacific mackerel were effectively extracted with 0.3% NaHCO₃-containing 0.15% NaCl, 0.15_M KCl, or a phosphate buffer (pH 7.5, I=0.05). The amounts of extracted ALD, GAPDH and GPI with 0.3% NaHCO₃-containing 0.15% NaCl were 1.5-4 times with that of distilled water. On the other hand, most of phosphoglycerate kinase and enolase was extracted in the absence of KCl.