Amidase trypsin

S. -H. Hung, L. Hedstrom, Converting trypsin to elastase substitution of the SI site and adjacent loops reconstitutes esterase specificity but not amidase activity, Prot. Eng. 1998, 11, 669-673. 

As one might expect, water has a dramatic effect on enzyme stability in SCFs. Lozano et al. found that the half-life time of a-chymotrypsin decreased exponentially in SCCO2 with increasing water content from 0 to 15 wt% [28]. Kashe et al. found that a-chymotrypsin, trypsin and penicillin amidase partially unfolded during pressure reduction in humid SCCO2. They suggested that... 

Specific peptidase and protease systems which involve Mn(II) include thrombin limited-proteolysis of prothrombin [122], insulin protease [123], enkephalin-degrading amino-peptidase [124], camosinase [125,129], ki-ninase [127], and trypsin activation [128]. A metalIo(Mn)-protease is involved in the processing of mitochondrial precursor proteins [130]. Several aminopeptidases are also specifically manganese-dependent, namely Leu-aminopeptidase [131] and prolidase or C-terminal proline dipeptidase [132-135]. Other systems that hydrolyze linear and cyclic G-N bonds include various amino-acylases, deacetylases, amidases and methylene-... 

If then, in the reconstruction of albuminoids enzymes really play a part, it cannot be the digestive enzymes such as pepsin and trypsin, but rather erepsin and the amidases, which apparently must have condensing properties like the preceding, and be, in addition, capable of reacting on the final products of hydrolysis. However, we do not possess at the present time data on the synthetic r61e of erepsin and the amidases. 

The transformation of curd into cheese is accomplished by the influence of various enzymes (i) galactase, a special trypsin, secreted by the mammary glamd simultaneously with the milk, an active substance of which we have previously had occasion to speak (2) pepsin, which is always found associated with rermet and which some writers even confound with it (3) various tryptases, or caseases, secreted by molds, bacteria, yeasts, etc., which develop on the surface or in the interior of the mass. To these enzymes, which dissolve casein and bring it to the simpler state of peptones, amino-acids, and ammonia, it is proper to add (4) amidases, that produce the formation of volatile acids (5) lactase and lactacidase, enzymes secreted by lactic bacilli, and which transform lactose into glucose and then into lactic add (6) lipases, which apparently decompose a part of the fatty material (7) finally oxidases, which bum the organic wastes, especially the adds. 

Figure 4 shows the temperature profiles for amidase activity of the protease from M. jannaschii at 10,250, and 500 atm. The optimum temperature for activity of 116° at low pressure (10 atm) is one of the highest optimum temperatures for a proteolytic enzyme reported in the literature. Figure 4 also shows that pressure substantially enhances the activity of the protease at each temperature for example, application of 500 atm increases the maximum reaction rate about twofold and the rate at 130°C fivefold. The 400% enhancement of amidase activity at 130° translates to an overall activation volume, A V, of — 106 ml mol , as determined by the Johnson-Eyring equation [Eq. (2)]. The most negative activation volumes previously reported for serine proteases were —36 ml mol for the digestion of casein by trypsin and —33 ml mol for the hydrolysis of Suc-Ala-Ala-pNA by a-chymotrypsin. Michels and Clark also found that the protease is stabilized... 

Leucine aminopeptidase R = r-Leucyl Trypsin, trypsiniiine amidase R = a-Benzoyl-L-arginine Peptidase R = Phenyi alanyl... 

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