CLONING OF THE PROLYL-DIPEPTIDYL-PEPTIDASE FROM ASPERGILLUS ORYZAE

摘要

The invention has for object the new recombinant prolyl-dipeptidyl-peptidase enzyme (DPP IV) from Aspergillus oryzae comprising the amino-acid sequence from amino acid 1 to amino acid 755 of SEQ ID NO:2 or functional derivatives thereof, and providing a high level of hydrolysing specificity towards proteins and peptides starting with X-Pro- thus liberating dipeptides of X-Pro type, wherein X is any amino acid. The invention also provides a DNA molecule encoding the enzyme according to the invention, cells expressing the enzyme according to the invention by recombinant technology, an Aspergillus naturally providing a prolyl-dipeptidyl-peptidase activity which has integrated multiple copies of the Aspergillus native promoter which naturally directs the expression of the gene encoding the prolyl-dipeptidyl-peptidase activity, Aspergillus naturally providing a prolyl-dipeptidyl-peptidase activity which is manipulated genetically so that the dppIV gene is inactivated. The invention provides a method for producing the enzyme according to the invention, comprising cultivating the cells of the invention in a suitable growth medium under conditions that the cells express the enzyme, and optionally isolating the enzyme in the form of a concentrate. The invention provides the use of the enzyme or the cells of the invention to hydrolyse protein containing materials. The invention provides the use of an enzyme and/or a cell providing a prolyl-dipeptidyl-peptidase activity, in combination with at least an enzyme providing a prolidase to hydrolyse protein containing materials. In a last further aspect, the invention provides a food product comprising a protein hydrolysate obtainable by fermentation with at least a microorganism providing a prolyl-dipeptidyl-peptidase activity higher than 50 mU per ml when grown in a minimal medium containing 1 % (w/v) of wheat gluten.