Pepsin chicken

Fig. 4.7.4. (A) Capacity of immobilized inhibitor sorbent (e-aminocaproyl-L-Phe-D-Phe-OMe-Separon) in mg of pepsin per g of dry sorbent, and (B) portion of immobilized inhibitor molecules involved in specific complex formation (in %) with respect to immobilized inhibitor concentration (in pmol of inhibitor per g of dry sorbent). -0-, porcine pepsin chicken pepsin, and human pepsin.

Gordin, S. and Rosenthal, I. 1978. Efficacy of chicken pepsin as a milk clotting enzyme. J. Food Prot. 41, 684-688. 

Green, M. L. 1972. Assessment of swine, bovine and chicken pepsins as rennet substitutes for Cheddar cheesemaking. J. Dairy Res. 39, 261-273. 

Stanley, D. W., Emmons, D. B., Modler, H. W. and Irvine, D. M. 1980. Cheddar cheese made with chicken pepsin. Can. Inst. Food Sci. Technol J. 13, 97-102. 

Heparin Growth factors, coagulation faaors, lipoproteins, DNA polymerase, DNA ligase, RNA polymerases, restriction endonucleases, polynucleotide kinase, lipoprotein lipase, hepatic triglyceride lipase, reverse transcriptase, hyaluronidase, neurauninidase, trypsin, pepsin, fumarase, lectin from chicken liver and embryonic chicken muscle, platelet-secreted antiheparin proteins, platelet-endoglycosidase... 

BSA monomer, ovalbumin (chicken), P-lactoglobulin (bovine milk), serum albumin (human), carbonic anhydrase (bovine), L-glutamic dehydrogenase (bovine liver), a-chymotrypsin (bovine), a-chymotrypsinogen A (bovine), immunoglobulin (bovine milk), pepsin, trypsin (bovine), and heparin were from Sigma. RNase and lysozyme (egg white) were from Calbiochem. The recombinant human basic fibroblast... 

Chicken pepsin is the least suitable of these and is used widely only in Israel. Bovine pepsin is probably the most satisfactory and many commercial calf rennets contain up to 50% bovine pepsin its proteolytic specificity is generally similar to that of calf chymosin. The proteolytic specificities of the three principal fungal rennets are considerably different from that of calf chymosin but the acceptability of most cheese varieties made using fungal rennets is fairly good. Microbial rennets are widely used in the United States but to only a limited extent in Europe. The extensive literature on rennet substitutes has been reviewed by Sardinas (1972), Emstrom and Wong (1974), Nelson (1975), Green (1977), and Phelan (1985). 

Chicken egg white Hydrolysis with pepsin Egg white hydrolysate Manso et al. (2008)... 

Purification of a cyclic nucleotide phosphodiesterase Affinity chromatography of carbohydrate-specific immunoglobulins Purification of chicken pepsin... 

Several pepsinogens and pepsins have been reported in dogfish and chickens, but we do not find the information sufficient to classify these enzymes in the general scheme suggested above. 

Central to the study of mechanism and specificity of the acid proteinases is a knowledge of the three-dimensional structures of enzymes with different physiological roles. The availability of acid proteinases with either extracellular or intracellular roles in vertebrates as well as similar enzymes from plants, protozoa, and fungi allows a wide range of comparative studies. In our laboratory we have undertaken the x-ray analysis of fungal enzymes, those from Endothia parasitica and Mucor pusillus, and some vertebrate enzymes including chymosin and chicken pepsin, and are beginning work with cathepsin D. 

We also have crystals of chymosin (6), the acid proteinase from Mucor pusillus (7), chicken pepsin (8), and chicken pepsinogen (8), the first two of which are large and very suitable for x-ray analysis. Dr. C. W. Bunn and his co-workers made preliminary x-ray studies of chymosin but the method of isomorphous replacement was unsuccessful, as simple heavy atom derivatives proved impossible to prepare. Both we and Professor B. Foltmann and Dr. S. Larsen of Copenhagen have continued x-ray studies on chymosin, but have also met difficulties. More recently, we have began to use the structural information from the Endothia parastica enzyme to solve the structure of chymosin by using the method of molecular replacement. 

Similar use of molecular replacement combined with refinement at high resolution appears to be the most hopeful method of defining the molecular structures of the enzymes from Mucor pusillus and chicken pepsin. 

The peptide fractions from activation of canine and chicken pepsinogens are shown in Table VII. The composition of canine pepsinogen is known (26) but that of the pepsin is not, so it is not possible to calculate a difference for the activation segment. Assuming a modest homology with the proteins in Figure 1, however, it seems reasonable to assume that about 50 residues should be released. Only about 22 amino acids were released in the presence of pepstatin. 

The compositions of chicken pepsinogen (27) and pepsin (27,28) are known and the difference calculated for the activation segment is given in Table VII Activation in the absence of pepstatin gave a peptide composition (Table VII) in reasonable agreement with these predicted values. In contrast, inclusion of pepstatin during the activation produced significantly smaller numbers of residues. 

The composition of the protein generated on activation of chicken pepsinogen in the absence of pepstatin (Table VIII) bears a marked resemblance to chicken pepsin (the low Met and Tyr values were due to poor hydrolysis conditions) whereas the protein obtained in the presence of pepstatin has a composition intermediate to those of the zymogen and pepsin and quite similar to the calculated values obtained by subtraction of the peptide composition (Table VII) from that of pepsinogen. 

By incubation of porcine, bovine, canine, or chicken pepsinogens and calf prochymosin with pepstatin at pH 2.5, the first active protein generated on activation is trapped in an inactive complex. The first activation peptide liberated from porcine pepsinogen has been identified as residues 1-16 whereas that from prochymosin is derived from residues 1-27. This suggests that pepsin and chymosin are not formed by one-step conversions from their zymogens, but by (different) sequential, activation mechanisms. 

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