Characterization and partial purification of acid lipase from human leucocytes

Area of Science:

• Biochemistry
• Cell Biology
• Enzymology

Background:

• Human leucocytes possess enzymatic activity for glycerol trioleate hydrolysis.
• Understanding these enzymes is crucial for comprehending lipid metabolism in immune cells.

Purpose of the Study:

• To characterize the enzymes responsible for glycerol trioleate hydrolysis in human leucocytes.
• To purify and determine the properties of these enzymes.

Main Methods:

• Gel chromatography (Sephadex G-100) and zonal ultracentrifugation were used for enzyme purification.
• Enzyme activity was localized to the granule fraction of leucocytes.
• pH optimum, molecular weights, and stability were determined.

Main Results:

• Two distinct proteins with molecular weights of approximately 74,100 and 60,300 Da were identified as responsible for hydrolysis.
• The optimal pH for activity was found to be 5.25.
• Enzyme activity was inhibited by NaCl, KCl, CaCl2, and p-hydroxymercuribenzoate.

Conclusions:

• Human leucocytes contain specific enzymes that hydrolyze glycerol trioleate.
• These enzymes are granule-associated and have distinct molecular weights and pH optima.
• Further characterization provides insights into leucocyte lipid metabolism.