Proteinases, acid

Female NMRI mice were exposed to 100 ppm of hydrogen sulfide for 2 hours at 4-day intervals excitement was observed (Savolainen et al. 1980). Exposure also resulted in decreased cerebral ribonucleic acid (RNA), decreased orotic acid incorporation into the RNA fraction, and inhibition of cytochrome oxidase. An increase in the glial enzyme marker, 2, 3 -cyclic nucleotide-3 -phosphohydrolase, was seen. Neurochemical effects have been reported in other studies. Decreased leucine uptake and acid proteinase activity in the brain were observed in mice exposed to 100 ppm hydrogen sulfide for 2 hours (Elovaara et al. 1978). Inhibition of brain cytochrome oxidase and a decrease in orotic acid uptake were observed in mice exposed to 100 ppm hydrogen sulfide for up to 4 days (Savolainen et al. 1980). 

While the majority of attention has focused on peptides contained within the nervous system, two other important methods for delivering peptides to the vicinity of the mast cell have been established (1) peptides produced and secreted by other cells of inflammation that may affect mast-cell function and (2) the local generation of mast-cell-active peptides by secreted enzymes acting on circulating protein precursors. Examples of the former include several, as yet ill-defined, peptide factors and cationic proteins from other immunocompetent cells [66-69], defined lymphokines such as the interleukin-1 [70] and interleukin-3 [71], and tumour necrosis factor [70], Examples of the latter include bradykinin [72] and a recently identified peptide produced by the action of acid proteinases on albumin [73, 74]. 

Aspartic endopeptidases (EC 3.4.23) are the best-known aspartic hydrolases and the only ones to be presented here. These enzymes were formerly called acid proteinases because most of them are active at low pH. In con-... 

Figure 4. Enzyme activities in analytical QM anion exchange column fractions detected with substrates selected for laccases, peroxidases (including ligninases), acid phosphatases, and acid proteinases. Major peaks are numbered. (Reproduced with permission from ref. 9. Copyright 1990 Society of Fermentation Technology, Japan.)...

Combinations of several enzymes with different specificities are required for complete degradation of proteins into free amino acids. Proteinases and peptidases are found not only in the gastrointestinal tract (see p. 268), but also inside the cell (see below). 

Increase in activity of cerebral succinic dehydrogenase and brain acid proteinase, and in brain RNA concentration decrease in liver cytochrome P-450 activity (22)... 

Nitromethane was administered intraperitoneally (200 mg/kg bw) to male Wistar rats (three months of age) as a 10% solution in olive oil. The effects of nitromethane in the liver were detected only 48 h after administration and included a decrease in NADPH-cytochrome c reductase activity with proliferation of the smooth endoplasmic reticulum. Nitromethane also caused an increase in brain acid proteinase (4 h after injection) and acetylcholine esterase activities (4, 24 and 48 h after injection) (Zitting etal, 1982). 

Kuba, M., Tana, C., Tawata, S., and Yasuda, M. (2005). Production of angiotensin-I converting enzyme inhibitory peptides from soybean protein with Monascus purpureus acid proteinase. Process Biochem. 40, 2191-2196. 

Cathepsin D (EC3.4.23.5). It has been known for more than 20 years that milk also contains an acid proteinase, (optimum pH ss 4.0) which is now known to be cathepsin D, a lysozomal enzyme. It is relatively heat labile (inactivated by 70°C x 10 min). Its activity in milk has not been studied extensively and its significance is unknown. At least some of the indigenous acid proteinase is incorporated into cheese curd its specificity on asl- and / -caseins is quite similar to that of chymosin but it has very poor milk-clotting activity (McSweeney, Fox and Olson, 1995). It may contribute to proteolysis in cheese but its activity is probably normally overshadowed by chymosin, which is present at a much higher level. 

M. Borg and R. Ruchel, Expression of extracellular acid proteinase by proteolytic Candida spp. during experimental infection of oral mucosa, Infect. Immun., 56, 626, 1988. 

Microbial proteinases can be classified by mechanism of action. Hartley (1960) divided them into four groups serine proteinases, thio proteinases, metalloproteinases, and acid proteinases. Morihara (1974) classified enzymes within these groups according to substrate specificity. Enzymes which split peptide substrates at the carboxyl side of specific amino acids are called carboxyendopeptidases, and those which split peptide substrates at the amino side of specific amino acids are called aminoendopeptidases. Acid proteinases, such as rennin and pepsin, split either side of specific aromatic or hydrophobic amino acid residues. The action of proteolytic enzymes on milk proteins has been reviewed by Visser (1981). 

Ichishima, E. (1970). Purification and mode of assay for acid proteinase of Aspergillus saitoi. In Perlmann, G. E., and Lorand, L. (Eds.), Methods in Enzymology Proteolytic Enzymes. Vol. XIX, (pp.397-406). New York Academic Press. 

Tanaka, N., Takeuchi, M., and Ichishima, E. (1977). Purification of an acid proteinase from Aspergillus saitoi and characterization of peptide bond specificity. Biochim. Biophys. Acta, 485, 406-416. 

Majima, E., Oda, K., Murao, S., and Ichishima, E. (1988). Comparative study on the specificity of several fungal aspartic and acidic proteinases towards the tetradecapeptide of arennin substrate. Agric. Biol. Chem., 52, HI-193. 

Morihara, K., and Oka, T. (1973). Comparative specificity of microbial acid proteinases for synthetic peptides. 3. Relationship with their tiypsinogen activating ability. Arch. Biochem. Biophys., 157, 561-572. 

RecA gene product from E. coli which cleaves bacteriophage A repressor The acid proteinase, renin, which cleaves angiotenginogen to ansiotensin... 

Hydrolysis of the casein micelle-stabilizing K-casein by the action of selected acid proteinases (rennets), and the resultant slow quiescent aggregation of the destabilized micelles in the presence of calcium ions ( 3 mM) at 30-36°C (e.g., for most rennet-curd cheeses such as Cheddar, Mozzarella and Gouda)... 

Ray TL, Payne CD, Soil DR Variable expression of Candida acid proteinase by switch phenotypes of individual Candida albicans strains. Clin Res 1988 36 687. 

Ray TL, Payne CD Scanning electron microscopy of epidermal adherence and cavitation in murine candidiasis A role for Candida acid proteinase. Infect Immun 1988 56 1942—1949. 

Aspergillopeptidase A (E.C. 3.4.4.17) is an acid proteinase from Aspergillus saitoi. This enzyme may be prepared and assayed by the procedures described by E. Ichishima, Methods Enzymol. 19, 397 (1970). 

Rennet Acidic Proteinase Mucor ssp. and Genetically Engineered Bacteria Calf Stomach Coagulation of Milk Proteins in Cheese Production... 

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