CONSTRUCTION OF STABLE, SPECIFIC FAT-DEGRADING ENZYMES WHICH MAY BE OF GREAT INTEREST AS ADDITIVES FOR DETERGENT OR AFTER IMMOBILIZATION ON SOLID SUPPORT COULD FORM AN EXCELLENT TOOL FOR THE SYNTHESIS OF LIPIDS OR PHOSPHOLIPIDS IN ENZYME REACTORS.
Most living organisms contain enzymes which selectively cleave certain bonds in fat thereby rendering them water soluble. Such enzymes may have industrial applications in the biotechnological production of water insoluble fine chemicals and as additives in washing detergents. This requires stable enzymes of a well defined (tailored) specificty.
A deeper insight into the specificity of (phospho)lipases, which degrade such related compounds as phospholipids and triglycerides, could lead to the design of enzymes with altered specificity for lipid molecules. As a starting point, the 3-dimensional model of the stable and high specific porcine pancreatic phospholipase A2 was used. Attempts were made to introduce by protein engineering changes that affect specificity, but not stability. For a rational design of these changes, more 3-dimensional structures are required. Thus a bacterial aspecific (phospho)lipase was isolated, characterized at the biochemical level and attempts were made to obtain its 3-dimensional structure.
The straphylococcal lipase was produced, purified and characterized. The enzyme can be described as a phospholipase A1 with significant lipase activity. Mutants were produced allowing for a more simplified purification and the introduction of a unique thiol group into the active site. Both mutations may increase the chance to solve its 3-dimensional structure. Several mutants of pancreatic phospholipase A2 were produced and characterized. 2 mutations are of special interest: mutant 1 has increase activity on neutral, but reduced activity on negatively charged phospholipids; mutant 2 has a changed chiral specificity in addition to elevated activity on uncharged phospholipids.
CONSTRUCTION BY GENETIC ENGINEERING OF AN ENZYME SHARING THE STABILITY PROPERTIES OF PHOSPHOLIPASE A2 WITH THE BROAD SUBSTRATE SPECIFICITY OF LIPASES.
BY GENETIC MANIPULATION A SERINE RESIDUE WILL BE INTRODUCED INTO THE ACTIVE SITE OF PANCREATIC PHOSPHOLIPASE A2 HAVING ITS OH FUNCTION AS CLOSE AS POSSIBLE TO THE ORIGINAL POSITION OF THE IMMOBILIZED H2O MOLECULE IN THE NATIVE MOLECULE.
TO BRIDGE THE GAP BETWEEN THE PANCREATIC PHOSPHOLIPASE A2 AND LIPASE, THE PHOSPHOLIPASE A2 AND LIPASE, THE PHOSPHOLIPASE A1 FROM ESCHERICHIA COLI WILL ALSO BE STUDIED IN DETAIL.
Funding SchemeCSC - Cost-sharing contracts