Enzyme trypsin

The proteolytic enzymes, trypsin, chymotrypsin, and chymoral [8076-22-0] in combination, have been used for the treatment of post-operative hand trauma, athletic injuries, and sciatica (214—216). Trypsin has also been used successfully in treating hyaline membrane disease of newborn babies, a condition usually fatal without treatment (217). Immobilized preparations of trypsin are useful in treating acute radiation cystitis following pelvic x-irradiation therapy (218). 

FIGURE 14.11 The pH activity profiles of four different enzymes. Trypsin, an intestinal protease, has a slightly alkaline pH optimnm, whereas pepsin, a gastric protease, acts in the acidic confines of the stomach and has a pH optimmn near 2. Papain, a protease found in papaya, is relatively insensitive to pHs between 4 and 8. Cholinesterase activity is pH-sensitive below pH 7 but not between pH 7 and 10. The cholinesterase pH activity profile suggests that an ionizable group with a pK near 6 is essential to its activity. Might it be a histidine residue within the active site ... 

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. 

Task (3) is more difficult. It uses a series of reagents each of which is capable of breaking only certain amide bonds. One of these reagents is the enzyme trypsin, which breaks only those bonds formed by the carboxyl groups in arginine and lysine. It would break the polypeptide... 

The serine proteases are the most extensively studied class of enzymes. These enzymes are characterized by the presence of a unique serine amino acid. Two major evolutionary families are presented in this class. The bacterial protease subtilisin and the trypsin family, which includes the enzymes trypsin, chymotrypsin, elastase as well as thrombin, plasmin, and others involved in a diverse range of cellular functions including digestion, blood clotting, hormone production, and complement activation. The trypsin family catalyzes the reaction ... 

An isolated flagellum will continue to bend actively, indicating that this function is linked to its intrinsic structure. Treatment of cilia from the protozoan Tetra-hymena with the proteolytic enzyme trypsin selectively dissolves the nexin links and radial spokes but leaves unaffected the microtubules and dynein arms. If such a preparation is treated with a small amount of ATP, the loosened microtubule doublets slide against each other and through longitudinal overlap, extend for a distance that is up to nine times the original length of the cilium (Warner and Mitchell, 1981). 

The use of glutaric dialdehyde as a coupling agent bound the enzymes trypsin or glucose-6-phosphate dehydrogenase to the surface. A large part of the enzymic activity was retained (Fig. 4), and the activity was such that the particle-enzyme conjugate could be used in laboratory scale continuous-flow reactors. 

The catalytic mechanism of the subtilisins is the same as that of the digestive enzymes trypsin and chymotrypsin as well as that of enzymes in the blood clotting cascade, reproduction and other mammalian enzymes. The enzymes are known as serine proteases due to the serine residue which is crucial for catalysis (Kraut, 1977 and Polgar, 1987)... 

Total PA activity Total PA activity Collagenase 1 Collagenase 1 CB-Iike enzyme Trypsin-like enzyme Chymotrypsin-like enzyme 92-kDa gelatinase Heparanase... 

Non-immunologic Trypsin-like enzymes Trypsin-like enzymes... 

LueBen, H.L., Verhoef, J.C., Borchard, G., Lehr, C.-M., De Boer, A.G., and Junginger, H.E., Mucoadhesive polymers in peroral peptide drug delivery. II. Carbomer and polycarbophil are potent inhibitors of the intestinal proteolytic enzyme trypsin, Pharm. Res., 12 1293-1298 (1995). 

A protein identification study might proceed in the following manner. Pirst, the protein is analyzed by mass spectrometry to determine its molecular mass to within 0.01%. Second, the protein is digested with an enzyme, commonly trypsin. The enzyme trypsin cleaves polypeptide chains at points following lysine and arginine residues. Using this proteolytic enzyme ensures that each... 

A large group of proteinases contain serine in their active center. The serine proteases include, for example, the digestive enzymes trypsin, chymotrypsin, and elastase (see pp. 94 and 268), many coagulation factors (see p. 290), and the fibrinolytic enzyme plos-min and its activators (see p. 292). 

Endothelial cells recovered from both the enzyme (trypsin) recovery system (ERS) and the poly(IPAAm) temperature recovery system (TRS) were subcultured and examined comparatively for cell adhesivity, cell morphology and cell growth activity. The most important finding in the subcultured system was that the TRS exhibited much a higher activity of prostacyclin generation than ERS. It is known that prostacyclin generation is an important function of endothelial cells. 

Large peptides are partially hydrolyzed with enzymes (trypsin and chymotropsin) or acid to mixtures of di- and tripeptides. From the composition of these small units we establish the sequence of amino acids in the large polypeptide. 

The mechanism of action of anticholinesterases is to form a stable covalent complex with the Achase enzyme. Achase is one of several enzymes known as serine esterases. Other examples include the intestinal enzymes trypsin and chymotrypsin as well as the blood clotting agent thrombin. During the course of the catalysis the alcohol -OH of a serine side chain in the active site of the enzyme forms an ester complex, called the acyl-enzyme, with the substrate. So, acetylcholine will go through similar chemical reactions with Achase. 

Among proteases, the digestive enzyme trypsin catalyzes the hydrolysis of only those peptide bonds in which the carbonyl group is contributed by either a Lys or an Arg residue, regardless of the length or amino acid sequence of the chain. The number of smaller peptides produced by trypsin cleavage can thus be predicted... 

The digestive enzymes trypsin, chymotrypsin, elastase, and proteinase E are related serine proteases. All three are synthesized in the pancreas which secretes 5-10 g per day of proteins, mostly the inactive proenzymes (zymogens) of digestive enzymes.191,192... 

The mammalian serine proteases have a common tertiary structure as well as a common function. The enzymes are so called because they have a uniquely reactive serine residue that reacts irreversibly with organophosphates such as diisopropyl fluorophosphate. The major pancreatic enzymes—trypsin, chymotrypsin, and elastase—are kinetically very similar, catalyzing the hydrolysis of peptides... 

Casein is not coagulated by heat. It is precipitated by acids and by rennin. a proteolytic enzyme obtained from the stomach or calves. Casein is a conjugated protein belonging lo the group uf phosphoproteins. The enzyme trypsin can hydrolyze off a phosphorus-containing peptone. 

Enzyme inhibitors of a protein nature are of significant concern because of widespread occurrence. The most common of these affect the pancreatic enzymes, trypsin and chymotrypsin. and arc found in legumes, as well as in egg whites and potatoes. 

NORTHRUP, JOHN H. (1891-1987). An American chemist who won a Nobel prize in chemistry in 1946 along with James B. Sumner and Wendell M. Stanley. His work was primarily concerned with isolation and crystallization of enzymes. Many first included the production of the enzyme trypsin in the laboratory and isolation of the first bacterial virus. He was also responsible for producing diphtheria antitoxin in crystalline form. His education was at eastern schools including Harvard. Yale, and Princeton. 

The inactive precursors are called trypsinogen, pepsinogen, chymotrypsino-gen, and procarboxypeptidase. These precursors are converted to the active enzymes by hydrolytic cleavage of a few specific peptide bonds under the influence of other enzymes (trypsin, for example, converts chymotrypsinogen to chymotrypsin). The digestive enzymes do not appear to self-destruct, probably because they are so constructed that it is sterically impossible to fit a part of one enzyme molecule into the active site of another. In this connection, it is significant that chymotrypsin attacks denatured proteins more rapidly than natural proteins with their compact structures of precisely folded chains. 

The proteolytic enzymes trypsin, chymotrypsin, and elas-tase, discussed later on, all work in this way. 

The serine proteases are a large family of proteolytic ( enzymes that use the reaction mechanism for nucleophilic catalysis outlined in equations (3) and (4), with a serine residue as the reactive nucleophile. The best known members of the family are three closely related digestive enzymes trypsin, chymotrypsin, and elastase. These enzymes are synthesized in the mammalian pancreas as inactive precursors termed zymogens. They are secreted into the small intestine, where they are activated by proteolytic cleavage in a manner discussed in chapter 9. 

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