Subcellular distribution and some properties of acid phospholipase A1 in rat testis.
The activity of phospholipase A was studied in homogenates, and mitochondria and lysosome-enriched fractions of rat testis. Using testicular homogenates and Triton X-100, phospholipase A1 activity with pH optima at 3.0 and 7.0 and phospholipase A2 activity with a pH optimum at 6.5 were observed. With optimum pH at 3.0, phospholipase A1 was further studied, identified and characterized by using 1-acyl-2-[1-(14)C]1 oleoyl-sn-glycero-3-phosphocholine as substrate in mitochondria and lysosome-enriched fractions. Acid phospholipase A1 activity was inhibited by Ca2+ and EDTA. The enzyme activity was greatly stimulated by Triton X-100, not inhibited by sulfhydryl reagents and DIFP, and relatively heat stable at 65 degrees C. Acid phospholipase A1 activity had properties similar to other phospholipases of lysosomal origin: subcellular distribution, metal independence and acid pH optimum and was mainly localized in mitochondria and lysosome-enriched fraction suggesting a lysosomal origin.
D000818:Animals; D004355:Drug Stability; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D008247:Lysosomes / Q000201:enzymology; D008297:Male; D010740:Phospholipases / Q000378:metabolism*; D010741:Phospholipases A / Q000037:antagonists & inhibitors / Q000378:metabolism*; D054466:Phospholipases A1; D054467:Phospholipases A2; D051381:Rats; D013347:Subcellular Fractions / Q000201:enzymology; D013737:Testis / Q000166:cytology / Q000201:enzymology*
D010740:Phospholipases; D010741:Phospholipases A; D054466:Phospholipases A1; D054467:Phospholipases A2