Aspergillus oryzae acid protease

Penicillopepsin Aspergillopeptidase A Aspergillus oryzae acid protease Rhizopus-pepsin Mucor rennins... 

Following Mosher s report, several publications appeared showing the preparation of Mosher s acid. One example is the chemoenzymatic preparation of Mosher s acid using Aspergillus oryzae protease (Scheme 1-5)24 ... 

Aspergillus oryzae protease Scheme 1-5. Chemoenzymatic preparation of Mosher s acid. 

Application and Principle This procedure is used to determine the proteolytic activity, expressed as hemoglobin units on the tyrosine basis (HUT), of preparations derived from Aspergillus oryzae var. and Aspergillus niger var., and it may be used to determine the activity of other proteases at pH 4.7. The test is based on the 30-min enzymatic hydrolysis of a hemoglobin substrate at pH 4.7 and 40°. Unhydrolyzed substrate is precipitated with trichloroacetic acid and removed by filtration. The quantity of solubilized hemoglobin in the filtrate is determined spectrophotometrically. 

However, if protease activity were involved, such preparations of methloninase from putIda could provide self-destructing enzyme systems for encapsulated, flavor-producing systems (65) that would prevent over-production of methanethiol and hydrogen sulfide. Alternatively, it might be possible to use other sources of methloninase, such as Brevlbacterlum linens (7 35) or Aspergillus oryzae (56, 57), as systems with potentially less protease activity. In any event further studies will be required to determine if alpha-ketobutyrlc acid assays provide suitable data for indexing methloninase activity In flavor systems. 

Dihydroisoxazole 1066 is obtained in nearly quantitative yield from the cycloaddition of ethyl methacrylate with ethoxycarbonylformonitrile oxide. Treatment of 1066 with protease from Aspergillus oryzae in a two-phase system (toluene and pH 7.0 buffer) results in an enantio-selective hydrolysis of the 5-carboxylate group, producing a mixture of (/ )-1067 (44.5% yield, 97% ee) and (5)-1068 (55% yield, 77% ee) when the reaction is terminated at 55% conversion. Hydrolysis of the diester 1067 and thermal decarboxylation of the resulting diacid (1069) affords (i )-3-cyano-2-hydroxy-2-methylpropanoic acid (1070). Acid catalyzed methanolysis of the nitrile group gives 1059 with > 97% ee. 

The use of subtilisin (a protease which is widely used in detergent formulations) as a biocatalyst for the stereospecific hydrolysis of esters is well established [271-273]. Along the same lines, a protease derived from Aspergillus oryzae, which has hitherto mainly been used for cheese processing, has been shown to be particularly useful for the resolution of sterically hindered substrates such as a,a,a-trisubstituted carboxylates [274] (Scheme 2.42). While traditionaT proteases such as subtilisin were plagued by slow reaction rates and low selectivities, the a-tri-fluoromethyl mandelic ester (which constitutes a precursor of a widely used chiral derivatization agent, Mosher s acid [275]) was successfully resolved by Aspergillus oryzae protease [276]. 

Extracellular Fungal Polysaccharides.—Neither of the two polysaccharides associated with the acid protease from Aspergillus oryzae is bound to the protein by a covalent linkage, although they may stabilize the protease during secretion. " ... 

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