Are monoglyceride-lipase, triglyceride-lipase and phospholipase A of rat liver microsomes distinct protein entities?
1. Different extraction and purification techniques were employed for the separation of MG-lipase, TG-lipase and phospholipase A from rat liver microsomes. 2. Up to 60 per cent of the microsomal content of TG-lipase and phospholipase could be extracted with 1 M KCl or NaCl. MG-lipase was extracted more readily by detergents (e.g. emulphogen). 3. MG-lipase is more resistant to detergent and heat inactivation than TG-lipase and phospholipase A. It is retained, using the technique of affinity chromatography, on a column of CH-Sepharose coupled to monooleoylglycerol. In addition, MG-lipase was separated from TG-lipase by electrofocusing. 4. TG-lipase and phospholipase A were partially separated by gel filtration on Sephadex G-200 in the presence of 1 mM dithiothreitol and by chromatography on CH-Sepharose 4b. 5. On the basis of the present extraction and purification studies, it is concluded that mg-lipase is an enzyme protein distinct from TG-lipase and phospholipase A.
D000818:Animals; D002846:Chromatography, Affinity; D003902:Detergents; D005989:Glycerides; D007700:Kinetics; D008049:Lipase / Q000302:isolation & purification / Q000378:metabolism; D008566:Membranes / Q000201:enzymology; D008862:Microsomes, Liver / Q000201:enzymology*; D009994:Osmolar Concentration; D010740:Phospholipases / Q000302:isolation & purification / Q000378:metabolism; D011189:Potassium Chloride; D051381:Rats; D012965:Sodium Chloride; D014280:Triglycerides
D003902:Detergents; D005989:Glycerides; D014280:Triglycerides; D012965:Sodium Chloride; D011189:Potassium Chloride; D010740:Phospholipases; D008049:Lipase