Peptide hydrolases

EE Sterchi, JF Woodley. Peptide hydrolases of the human small intestinal mucosa Distribution of activities between brush border membranes and cytosol. Clin Chim... 

C Shoaf, RM Berko, WD Heizer. Isolation and characterization of four peptide hydrolases from the brush border of rat intestinal mucosa. Biochem Biophys Acta 445 649-719, 1976. 

The NC-IUBMB has introduced a number of changes in the terminology following the proposals made by Barrett, Rawlings and co-workers [7] [8]. The term peptidase should now be used as a synonym for peptide hydrolase and includes all enzymes that hydrolyze peptide bonds. Previously the term peptidases was restricted to exopeptidases . The terms peptidase and protease are now synonymous. For consistency with this nomenclature, the term proteinases has been replaced by endopeptidases . To complete this note on terminology, we remind the reader that the terms cysteine endopeptidases and aspartic endopeptidases were previously called thiol proteinases and acid or carboxyl proteinases , respectively [9],... 

Peptide hydrolases (peptidases or proteases, i.e., enzymes hydrolyzing peptide bonds in peptides and proteins, see Chapt. 2) have received particular attention among hydrolases. As already described in Chapt. 2, peptidases are divided into exopeptidases (EC 3.4.11 -19), which cleave one or a few amino acids from the N- or C-terminus, and endopeptidas-es (proteinases, EC 3.4.21-99), which act internally in polypeptide chains [2], The presentation of enzymatic mechanisms of hydrolysis in the following sections will begin with peptidases and continue with other hydrolases such as esterases. 

The results showed a 59% confirmation rate (41% false positive rate), giving 4296 confirmed actives. Of the compounds initially selected with >40% inhibition, 69% confirmed at >40% inhibition. This can be broken down further into compounds that feU into enriched clusters and those that did not, with confirmation rates of 73 and 68% respectively. In this case, there was only a modest increase in the confirmation rate for compounds selected from enriched clusters. This might be attributed to the fact that the enrichment within the active clusters was only about 50% greater than the background hit rate (21 versus 14.7%) in contrast to the peptide hydrolase case where the enrichment was 2.6-fold higher. 

The confirmed actives selected from each of the three example projects shown are at varying stages of progression through the secondary assay process. The peptide hydrolase example is the most advanced and so has the most information available. The throughput limit for secondary assays in that case was just 500 molecules, and... 

El Soda, M., Bergere, J. L. and Desmazeaud, M. J. 1978A. Detection and localization of peptide hydrolases in Lactobacillus casei. J. Dairy Res. 5, 519-524. 

Pacquet, J. and Gripon, J. C. 1980. Intracellular peptide hydrolases of Penicillium ro-queforti. Milchwissenschaft 35, 72-74. 

Torgersen, H. and Sorhaug, T. 1978. Peptide hydrolases of Brevibacterium linens. FEMS Microbiol. Lett. 4, 151-153. 

The International Union of Biochemistry and Molecular Biology recommends that the term peptidase be used synonymously with the term peptide hydrolase (IUBMB, 1992). Thus, in this unit the term peptidase is used in reference to any enzyme that catalyzes the hydrolysis of peptide bonds, without distinguishing between exo- and endopeptidase activities. Peptidases may be assayed using native or modified proteins, peptides, or synthetic substrates. In this unit, the focus is on assays based on the hydrolysis of common, commercially available, protein substrates. Thus, the assays are not intended to be selective for a given peptidase they are designed to provide estimates of overall peptidase activity. Other units in this publication focus on synthetic or model substrates, which can be designed for the measurement of specific endo- and/or exopeptidase activities. 

Stauffer, C.E. 1989. Peptide hydrolases. In Enzyme Assays for Food Scientists, pp. 133-161. VanNos-trand Reinhold, New York. 

Inulase (C) Peptide hydrolases Yeast, artichokes, Dahlia Inulin Fructose... 

Rollan, G., de Valdez, G.F. 2001. The peptide hydrolase system of Lactobacillus reuteri. Int J Food Microbiol 70 303-307. 

A different type of peptide hydrolase, dipeptide transferase, catalyzed the oligomerization of dipeptide amides. In the case of glycyl-L-tyrosinamide, the corresponding oligomer with DP up to 8 was formed.242... 

Aminopeptidase P (aminoacyl-peptide hydrolase) Endothelial membrane... 

Many enzymes have common names that provide little information about the reactions that they catalyze. For example, a proteolytic enzyme secreted by the pancreas is called trypsin. Most other enzymes are named for their substrates and for the reactions that they catalyze, with the suffix ase" added. Thus, a peptide hydrolase is an enzyme that hyrolyzes peptide bonds, whereas ATP synthase is an enzyme that synthesizes ATP. 

The 20S proteasome is a multicatalytic protease containing several active centers. These are located in the hole of the cyhnder and are encoded by the j3-subunits. The 20S proteasome acts independently of ATP or any other factor. It is able to degrade unfolded proteins since those can enter the active centers of the proteasome through the opening formed by the a-subunits. This opening is usually covered by domains of the a-subimits and the active center is therefore only accessible after a certain activation of the proteasome. The 20S proteasome is able to cleave proteins on the carboxyl side ofbasic, hydrophobic, and acidic amino acids, described as a trypsin-hke, chymotrypsin-like, and peptidylgluamyl-peptide hydrolase-like proteolytic activity. 

Angiotensin-converting enzyme (ACE, peptidyl peptide hydrolase) (from rabbit lung) [9015-82-1] M 129,000 Dal (equilibrium sedimentation), Mr 140,000 (SDS-PAGE) [EC... 

Hydrolases. Acting on peptide bonds (peptide hydrolases). 3.4.-.-... 

---