Gastric- and lingual lipases are the two acidic lipolytic enzymes that origin preduodenal but the gastric lipase is in much higher levels in humans.  
Gastric lipase is synthesized and secreted from gastric chief cells in the stomach and is stable at pH 1,5-8,
but has maximum activity at pH 3-6.
Fat digestion begins when gastric lipase hydrolyses dietary triglycerides, by cleaving only one long-, medium- or short-acyl chain from the glyceride backbone and release free fatty acids and diacylglycerols. The enzyme hydrolyses esters at position sn-3, the acyl chain at the bottom,  more rapidly than esters at sn-1 position, the acyl chain on the top of the glyceride backbone. However the gastric lipase activity against phospholipids and cholesterol esters is poor.
Gastric lipase is composed of 379 amino acids. Fully glycosylated protein is 50kDa and unglycosylated enzyme is 43kDa. However deglycosylation of the enzyme does not affect the activity of the enzyme. The hydrophobic region around Ser152, which has the hexapeptide sequence Val-Gly-His-Ser-Gln-Gly, is essential for the catalytic activity of gastric lipase. At the N-terminal, Lys4 is necessary for the enzyme to bind at lipid-water interfaces.