Protease region

Table 7-1. Amino acid sequences in the neighborhood of the catalytic sites of several bovine proteases. Regions shown are those on either side of the catalytic site seryl (S) and histidyl (H) residues.

Genotypic resistance assays use DNA sequencing methods to examine the reverse transcriptase and protease regions of fhe HIV genome for all resistance-associated mutations. A major drawback of fhis fesfing mefhod is that results are difficult to interpret and expert consultation is necessary. 

Figure 9. Organization of the genes for factor Xll (197), urokinase (213), tissue-type plasminogen activator tPA (210,111) and factor XI (214). For abbreviations, see the legends to Figures 2 and 4. The protease regions of these genes are very similar and are shown in Figure 11.

A Sail, R Matsumoto, HP McNeil, M Karplus, RL Stevens. Three-dimensional models of four mouse mast cell chymases. Identification of proteoglycan-bmdmg regions and protease-specific antigenic epitopes. I Biol Chem 268 9023-9034, 1933. 

Figure 6.23 Schematic diagram illustrating the active site loop regions (red) in three forms of the serpins. (a) In the active form the loop protrudes from the main part of the molecuie poised to interact with the active site of a serine proteinase. The first few residues of the ioop form a short p strand inserted between ps and pis of sheet A. (h) As a result of inhibiting proteases, the serpin molecules are cleaved at the tip of the active site ioop region, in the cleaved form the N-terminal part of the loop inserts itself between p strands 5 and 15 and forms a long p strand (red) in the middie of the p sheet, (c) In the most stable form, the latent form, which is inactive, the N-terminai part of the ioop forms an inserted p strand as in the cleaved form and the remaining residues form a ioop at the other end of the p sheet. (Adapted from R.W. Carreii et ai., Structure 2 257-270, 1994.)...

A Scheme for the preparation of a series of eyelie urea HIV protease inhibitors eontaining alkynyl-tethered heteroeyeles in the P2 region ineludes hydrogenation with LiAlH4 in THF in 60-80% yields (96BMCL797) (Sehemes 83 and 84). 

Thompson, J. F., et al. (1997). Mutation of a protease-sensitive region in firefly luciferase alters light emission properties. J. Biol. Chem. 272 18766-18771. 

The nonstructural region of the precursor, harboring the viral replication machinery, is cut into its mature components in a maturation reaction in which two viral proteases (NS2-pro and NS3/4A-pro) cooperate. Site-directed mutagenesis of an other wise infectious cDNA has shown that both HCV-encoded proteases are necessary for viral infectivity, but most of the attention has so far been focused on one of them a member of the serine protease family (EC 3.4.21) located in the N-terminal region of the viral NS3 protein. 

Kaartinen M, Penttila A, Kovanen PT Accumulation of activated mast cells in the shoulder region of human coronary atheroma, the predilection site of atheromatous rupture. Circulation 1994 90 1669. Kaartinen M, Penttila A. Kovanen PT Mast cells of two types differing in neutral protease composition in the human aortic intima. Demonstration of tryptase- and tryptase/chymase-containing mast cells in normal intimas, fatty streaks, and the shoulder region of atheromas. Arterioscler Thromb 1994 14 966. 

The proteases are secreted as inactive zymogens the active site of the enzyme is masked by a small region of its peptide chain, which is removed by hydrolysis of a specific peptide bond. Pepsinogen is activated to pepsin by gastric acid and by activated pepsin (autocatalysis). In the small intestine, trypsinogen, the precursor of trypsin, is activated by enteropeptidase, which is secreted by the duodenal epithelial cells trypsin can then activate chymotrypsinogen to chymotrypsin, proelas-tase to elastase, procarboxypeptidase to carboxypepti-dase, and proaminopeptidase to aminopeptidase. 

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