An improved solid phase process for peptide synthesis wherein all steps of the synthesis are carried out in a solvent which produces a highly swollen state in the resin and wherein the coupling agent employed is one which forms by-products which are soluble in the solvent.
A composition which is either polystyrene or a substituted polystyrene crosslinked with divinylbenzene and swollen by N-methyl-2-pyrrolidone, which composition is useful in purifying blocked synthetic peptides by means of gel exclusion chromatography and in solid-phase peptide synthesis.
Blocked peptides are purified by gel exclusion chromatography, wherein the resin is polystyrene crosslinked with divinylbenzene and the solvent is N-methyl-2-pyrrolidone.
The present invention provides substantially purified cryptdin peptides having a consensus amino acid sequence as follows: X.sub.1 -C-X.sub.2 -C-R-X.sub.3 -C-X.sub.4 -E-X.sub.5 -G-X.sub.6 -C-X.sub.7 -C-C-X.sub.8 wherein X.sub.1 is 3-6 amino acids; X.sub.2 is one amino acid; X.sub.3 is 2 or 3 amino acids; X.sub.4 is three amino acids; X.sub.5 is three amino acids; X.sub.6 is one amino acid; X.sub.7 is 6 to 10 amino acids; and X.sub.8 is 0 to 7 amino acids. The invention further provides substantially purified cryptdin peptides having a consensus amino acid sequence as follows: X.sub.1 -L-X.sub.2 -C-Y-C-R-X.sub.3 -C-K-X.sub.4 -E-R-X.sub.5 -G-T-C-X.sub.6 -C-C-X.sub.7 wherein X.sub.1 is one to four amino acids; X.sub.2 is one amino acid; X.sub.3 is three amino acids; X.sub.4 is two amino acids; X.sub.5 is two amino acids; and X.sub.6 is six to nine amino acids; and X.sub.7 is zero to seven amino acids. The illustrated embodiments have amino acids selected from the group consisting of the following sequences: LRDLVCYCRSRGCKGRERMNGTCRKGHLLYTLCCR LRDLVCYCRTRGCKRRERMNGTCRKGHLMYTLCCR LRDLVCYCRKRGCKRRERMNGTCRKGHLMYTLCCR GLLCYCRKGHCKRGERVRGTCGIRFLYCCPR LSKKLICYCRIRGCKRRERVFGTCRNLFLTFVFCC LKQCHCRKFCRPYEKAEGSCRPGLFIKRKICCIQQWTPG In another embodiment, the inventions provide analogs devoid of amino acids to the N-terminal of the first cysteine. Cryptdins are typically characterized by being naturally found in the epithelial cells of the small intestine being cationic, being between 30 and 40 amino acids in length, having 3 to 6 amino acids to the N-terminal of the first cysteine residue, exhibiting specific antimicrobial activity against intestinal pathogens and being relatively non-toxic to cells of the host organism. However, there may be diversity in these structural and functional characteristics. The present invention provides a method for detecting inflammatory pathologies in the subject and, further, provides a method for treating an infectious process of the intestine or other organ of the patient by administering cryptdin in a physiologically acceptable medium.
Site-specific modified proteins and method for producing site-specific modified proteins using amino acid analogs are disclosed. Methods for labeling proteins at a desired site in the presence of nucleophilic side chains, including lysine and cysteine side chains, are also disclosed. Methods for labeling the site-specific modified proteins are also disclosed.
Peptides and Peptide amides such as cholecystokinin (CCK-8) are synthesized in improved yields and purity by a solid phase process. The requisite protected peptide is elaborated and sulfated on a solid support, deprotected, and cleaved from the solid support to give the total synthesis of CCK-8 on a solid support. Thereafter, the peptide is purified in a single step by ion exchange chromatography to provide analytically pure CCK-8.
