Leucine-Rich Peptide Compositions and Methods for Isolation

Abstract

Disclosed are compositions comprising isolated peptides having a leucine content of from about 12 to about 40 weight percent. Also disclosed is a method for isolating leucine-rich peptides from protein sources such as bovine whey and methods of use for these peptides to provide beneficial effects in a human and/or animal such as increasing blood flow, decreasing blood pressure, increasing muscle mass, improving cognitive function, improving cardiovascular function, etc.

1 . A composition comprising isolated peptides having a leucine content of from about 12% to about 40% by weight and a molecular weight of from about 200 to about 4,000. 
     
     
         2 . The composition of  claim 1  wherein the leucine content of the isolated peptides is from about 12% to about 30% by weight. 
     
     
         3 . The composition of  claim 1  wherein the leucine content of the isolated peptides is from about 15 to about 20 weight percent. 
     
     
         4 . The composition of  claim 1  wherein the leucine content of the isolated peptides is from about 15 to about 30 weight percent. 
     
     
         5 . The composition of  claim 1  wherein the leucine content of the isolated peptides is from about 20 to about 30 weight percent. 
     
     
         6 . The composition of  claim 1  wherein the molecular weight of the isolated peptides is from about 200 to 1,000. 
     
     
         7 . The composition of  claim 1  wherein the molecular weight of the isolated peptides is from about 400 to 1,000. 
     
     
         8 . The composition of  claim 1  wherein the protein source is chosen from the group consisting of legumes, fish, meat, milk, egg, corn, wheat gluten, maize, and combinations thereof. 
     
     
         9 . The composition of  claim 1  wherein the protein sourceis chosen from the group consisting of bovine milk, bovine whey, whey protein concentrates, whey protein isolates, and combinations thereof. 
     
     
         10 . A peptide composition comprising peptides having a leucine content of from about 12 to about 40 weight percent and a molecular weight from about 200 to about 4,000, the peptides isolated from a protein source by a method comprising the steps of
 a) hydrolyzing the protein in the presence of at least one leucyl aminopeptidase to form a protein hydrolysate;   b) deactivating the aminopeptidase; and   c) filtering the protein hydrolysate to produce a permeate containing the leucine-rich peptides.   
     
     
         11 . A peptide composition as in  claim 10 , wherein the method comprises the additional step of concentrating the peptides by removing aqueous fluid from the permeate. 
     
     
         12 . The peptide composition of  claim 10  wherein the protein source is chosen from among the group consisting of legumes, fish, meat, milk, blood, egg, corn, wheat gluten, maize, and combinations thereof. 
     
     
         13 . The peptide composition of  claim 10  wherein the protein source is chosen from among the group consisting of bovine milk, bovine whey, whey protein concentrates, whey protein isolates, and combinations thereof. 
     
     
         14 . A method for isolating leucine-rich peptides from a protein source, the method comprising the steps of
 a) hydrolyzing the protein in the presence of at least one leucyl aminopeptidases to form a protein hydrolysate,   b) deactivating the aminopeptidase, and   c) filtering the protein hydrolysate to produce a permeate containing the leucine-rich peptides.   
     
     
         15 . The method of  claim 14 , further comprising the step of concentrating the peptides by removing aqueous fluid from the permeate. 
     
     
         16 . The method of  claim 14  wherein the protein source is chosen from among the group consisting of legumes, fish, meat, milk, blood, egg, corn, wheat gluten, maize, and combinations thereof. 
     
     
         17 . The method of  claim 14  wherein the step of filtering is performed to collect leucine-rich peptides having a molecular weight of from about 200 to about 4,000 in the permeate. 
     
     
         18 . The method of  claim 14  wherein the step of filtering is performed to collect leucine-rich peptides having a molecular weight of from about 200 to about 1,000. 
     
     
         19 . The method of  claim 14  wherein the step of filtering is performed to collect leucine-rich peptides having a molecular weight of from about 400 to about 1,000. 
     
     
         20 . The method of  claim 14  wherein the protein source is chosen from among the group consisting of bovine milk, bovine whey, whey protein concentrates, whey protein isolates, and combinations thereof. 
     
     
         21 . The method of  claim 14  wherein the leucine content of the peptides is from about 12 to about 30 weight percent leucine. 
     
     
         22 . The method of  claim 14  wherein the leucine content of the peptides is from about 15 to about 25 weight percent leucine. 
     
     
         23 . The method of  claim 14  wherein the leucine content of the peptides is from about 20 to about 25 weight percent leucine. 
     
     
         24 . A method for increasing nitric oxide production in the blood vessels of a subject, the method comprising administering to the subject an effective amount of a peptide composition comprising leucine-rich peptides having a leucine content of from about 12 to about 40 weight percent. 
     
     
         25 . The method of  claim 24  wherein the leucine-rich peptides are isolated from a protein source by a method comprising the steps of
 a) hydrolyzing the protein in the presence of at least one leucyl aminopeptidase to form a protein hydrolysate;   b) deactivating the aminopeptidase; and   c) filtering the protein hydrolysate to produce a permeate containing the leucine-rich peptides.   
     
     
         26 . The method of  claim 24  wherein the method for isolating the leucine-rich peptides further comprises the step of concentrating the peptides by removing aqueous fluid from the permeate. 
     
     
         27 . A method for producing vasodilation in the blood vessels of a subject, the method comprising administering to the subject an effective amount of a composition comprising leucine-peptides having a leucine content of from about 12 to about 40 weight percent. 
     
     
         28 . The method of  claim 27  wherein the leucine-rich peptides are isolated from a protein source by a method comprising the steps of
 a) hydrolyzing the protein in the presence of at least one aminopeptidase to form a protein hydrolysate;   b) deactivating the aminopeptidase; and   c) filtering the protein hydrolysate to produce a permeate containing the leucine-rich peptides.   
     
     
         29 . The method of  claim 27  wherein the method for isolating the leucine-rich peptides further comprises the step of concentrating the peptides by removing aqueous fluid from the permeate. 
     
     
         30 . A method for increasing blood flow in the blood vessels of a subject, the method comprising administering to the subject an effective amount of a composition comprising leucine-rich peptides having a leucine content of from about 12 to about 40 weight percent. 
     
     
         31 . The method of  claim 30  wherein the leucine-rich peptides are isolated from a protein source by a method comprising the steps of
 a) hydrolyzing the protein in the presence of one or more aminopeptidase to form a protein hydrolysate;   b) deactivating the aminopeptidase; and   c) filtering the protein hydrolysate to produce a permeate containing the leucine-rich peptides.   
     
     
         32 . The method of  claim 31  wherein the method for isolating the leucine-rich peptides further comprises the step of concentrating the peptides by removing aqueous fluid from the permeate.