Peptides enzymatic

Bioactive peptides as products of hydrolysis of diverse marine invertebrate (shellfish, crustacean, rotifer, etc.) proteins are the focus of current research. After much research on these muscles and byproducts, some biologically active peptides were identified and applied to useful compounds for human utilization. This chapter reviews bioactive peptides from marine invertebrates in regarding to their bioactivities. Additionally, specific characteristics of antihypertensive, anti-Alzheimer, antioxidant, antimicrobial peptide enzymatic production, methods to evaluate bioactivity capacity, bioavailability, and safety concerns of peptides are reviewed. 

Surface-active peptides Enzymatic digest /3-lactoglobulin... 

Bioactive peptides Enzymatic hydrolysate Milk, casein... 

Antimicrobial peptides Enzymatic digest or free peptides Several sources... 

The inducibility of Prl by proteinaceous compounds released enzymatically from insect cuticle was also studied inM anisopliae (Paterson et al., 1994b). In the case of Schistocerca gregaria cuticle treated with KOH in order to remove proteins, no induction of Prl production was observed, while cuticle treated with chloroform or ether to remove lipids was able to induce enzyme production. Digestion of cuticle with Prl or the trypsin-like protease Pr2 ofM anisopliae resulted in peptides mainly in the range of 150-2000 Da. The addition of these peptides at 3 pg Ala equivalents ml"1 led to the induction of Prl production to a level (75%) similar to that observed in the case of untreated insect cuticle. The ability of various amino acids and peptides abundant in insect cuticular protein (Ala, Gly, Ala-Ala, Ala-Ala-Ala, Ala-Pro and Pro-Ala) to induce Prl was tested but none of them was found to increase enzyme production in the levels observed with cuticle, or peptides enzymatically released from the cuticle. 

Improved stability of the therapeutic agents Encapsulation of the therapeutic agents in the microemulsion structures can offer improvement in the chemical, photochemical and enzymatic stability of the therapeutic agents such as chloramphenicol (chemical stability) [5], arbutin (photostability) [6] and peptides (enzymatic stability)... 

Most prominently, many spider species utilize amino acid-derived acylpolyamines as part of their venom. Similar to other venomous animals, spiders produce complex mixtures of biologically active compounds in their venoms, which in addition to acylpolyamines often contain free amino acids, peptides, enzymatically... 

Immunomodulating peptides. Enzymatic digests of human caseins contain immunomodulating peptides which stimulate the phagocytic activity of human macrophages in vitro and exert a protective effect in vivo in mice against Klebsiella pneumoniae infection. Two of the peptides were characterized as H.Val.Glu.Pro.Ile.Pro.Tyr (/6-CN f54-59) and H.Gly.Leu.Phe (origin not identified). 

Koglin A, Walsh CT (2009) Stmctural Insights into Nonribosomal Peptide Enzymatic Assembly Lines. Nat. prod. rep. 26 p. 987-1000. 

GLP-1 peptide enzymatic preparation of ( -amino-3-[3- 6-(2-metliylphenyl) pyridyQ-propionic acid. 

Whereas acid catalyzed hydrolysis of peptides cleaves amide bonds indiscriminately and eventually breaks all of them enzymatic hydrolysis is much more selective and is the method used to convert a peptide into smaller fragments... 

A typical TIC chromatogram from an analysis of peptides resulting from enzymatic digest of myoglobin. The peaks represent individual peptides eluting from an LC column and being mass measured by a spectrometer coupled to it through a dynamic-FAB inlet/ion source. 

The enzymatic hydrolysates of milk casein and soy protein sometimes have a strong bitter taste. The bitter taste is frequently developed by pepsin [9001 -75-6] chymotrypsin [9004-07-3] and some neutral proteases and accounted for by the existence of peptides that have a hydrophobic amino acid in the carboxyhc terminal (226). The relation between bitter taste and amino acid constitution has been discussed (227). 

Peptide Synthesis. The literature on the enzymatic synthesis of peptides is enormous (120—124). Here the basic principles that govern peptide synthesis are illustrated and recent trends in this area reviewed. 

ENZYMATIC ANALYSIS WITH CARBOXYPEPTIDASES. Carboxypeptidases are enzymes that cleave amino acid residues from the C-termini of polypeptides in a successive fashion. Four carboxypeptidases are in general use A, B, C, and Y. Carboxypeptidase A (from bovine pancreas) works well in hydrolyzing the C-terminal peptide bond of all residues except proline, arginine, and lysine. The analogous enzyme from hog pancreas, carboxypeptidase B, is effective only when Arg or Lys are the C-terminal residues. Thus, a mixture of carboxypeptidases A and B liberates any C-terminal amino acid except proline. Carboxypeptidase C from citrus leaves and carboxypeptidase Y from yeast act on any C-terminal residue. Because the nature of the amino acid residue at the end often determines the rate at which it is cleaved and because these enzymes remove residues successively, care must be taken in interpreting results. Carboxypeptidase Y cleavage has been adapted to an automated protocol analogous to that used in Edman sequenators. 

The enzymatic cleavage of esters is a vast and extensively reviewed area of chemistry. Recently, several new esters have been examined primarily for the preparation of peptides and glycopeptides. 

The choline ester is prepared by treating the 2-bromoethyl ester with trimethyl-amine. The ester is cleaved with butyrylcholine esterase (pH 6, 0.05 M phosphate buffer, rt, 50-95% yield). As with the morpholinoethyl ester, the choline ester imparts greater solubility to the C-terminal end of very hydrophobic peptides, thus improving the ability to cleave enzymatically the C-terminal ester. ... 

This amide, readily formed from an amine and the anhydride or enzymatically using penicillin amidase, is readily cleaved by penicillin acylase (pH 8.1, A -methylpyrrolidone, 65-95% yield). This deprotection procedure works on peptides, phosphorylated peptides, and oligonucleotides, as well as on nonpeptide substrates. The deprotection of racemic phenylacetamides with penicillin acylase can result in enantiomer enrichment of the cleaved amine and the remaining amide. An immobilized form of penicillin G acylase has been developed. ... 

Partial hydrolysis of a peptide can be carried out either chemically with aqueous acid or enzymatically. Acidic hydrolysis is unselective and leads to a more or less random mixture of small fragments, but enzymatic hydrolysis is quite specific. The enzyme trypsin, for instance, catalyzes hydrolysis of peptides only at the carboxyl side of the basic amino acids arginine and lysine chymotrypsin cleaves only at the carboxyl side of the aryl-substituted amino acids phenylalanine, tyrosine, and tryptophan. 

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