• Microbiology and Biotechnology Letters
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• v.1 no.2
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• pp.99-104
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• 1973

A study on the active center of the acid protease from Penicillium sp. was conducted, and also the milk clotting activity of acid prorease was measured. 1. PCMB failed to influence the proteolytic activity of acid protease, indicating that a reactive sulfhydryl group is not required for the enzymatic activity. 2. $\varepsilon$-amino caproic acid did not show any inhibitory effect on tile proteolytic activity of acid protease. 3. Also 2, 4-dinitro phenol did not show any inhibitory effect on the enzyme activity. 4. Acid protease from Penicillium sp. showed a strong milk clotting activity in the presence of Ca ion. 5. This enzyme had a strong proteolytic activity on various substrate, such as casein, denatured hemoglobin, ovalbumin, denatured bovine muscle protein, denatured percine muscle protein and denatured chicken muscle protein.

• Korean Journal of Microbiology
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• v.10 no.2
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• pp.69-72
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• 1972

The studies of neutral protease which was obtained by passing through Sephadex A-50 had been reported not long ago. Since that time the author also conducted the research to be investigated the physical properties of acid protease absorbed by Sephadex A-50. The results are summarized as follows : 1) Cultivating Aspergillus oryza SHW-131 on a wheat bran medium, the acid protease including neutral protease is very sensitive for temperature. 3) Activity of acid protease is very sensitive for temeprature. 3) This enzyme was proved, what is called, to be a sort of weak acid protease. It's optimum pH was lied in about 4.5. 4) A range of pH for stability is far more narrow than any other protease. 5) The acid protease is dropped by EDTA solution in its activity.

• Microbiology and Biotechnology Letters
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• v.8 no.2
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• pp.77-85
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• 1980

This experiment was conducted to investigate the conditions for production and the characteristics of pretenses. Aspergillus oryzae KC-15, which is selected as a superior strain for the production of the protease, was used in this study. The results obtained were as follows: 1. The optimum culture time for the production of acid, neutral and alkaline protease on wheat bran medium were about 48, 48 and 72hr, respectively. The protease-produced by the strain were mainly alkaline and neutral one, but the production of acid protease was feeble extremely. 2. The addition of NaH$_2$PO$_4$, Na$_2$HPO$_4$, glucose, rice powder and Na-glutamate respectively to wheat bran media were effective for the production of alkaline and neutral protease, and the addition of (NH$_4$)$_2$HPO$_4$, glucose and rice powder respectively were effective for the production of acid protease. 3. Characteristics of professes(equation omitted) 4. As a heat resistance agent, NaH$_2$PO$_4$was the most effective one. The optimum amount of NaH$_2$PO$_4$was 10mg for alkaline and neutral protease, and 5mg for acid protease. 5. The heat resistance of the Protease by NaH$_2$PO$_4$was not recognized mostly above 6$0^{\circ}C$. 6. After the treatment of enzyme solution with 10mg of NaH$_2$PO$_4$for 30 minutes at 55$^{\circ}C$, the residual activities measured for alkaline, neutral and acid protease were 58, 57 and 55％ respectively.

• Journal of Life Science
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• v.7 no.3
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• pp.228-233
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• 1997

A thiol protease has been isolated and partially purified from encysted brine shrimp Artemia franciscana using a four-step procedure(filtration, salting out, gel filtration and ion exchange chromatography). The optimum pH of the enzyme for caseinolytic activity was appeared to be 3.0, and the enzymematic activity was stable up to pH 6.0 but lost completely at the pH higher than 8.0. The optimal temperature of the enzyme was appeared to be 35$^{\circ}$C, and ninety percent of the enzyme activity was lost at 45$^{\circ}$C. Various metal ions, e.g., zinc, copper, iron, inhibited the enzyme activity; however, heavy metal chelator, e.g., EDTA, stimulated the enzyme activity. The protease was concluded to be a member of the thiol group protease, since it was inhibited by thiol protease inhibitors and iodoacetate. The protease was also concluded to be a acid protease based on optimum pH.

• Korean Journal of Microbiology
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• v.40 no.1
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• pp.12-16
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• 2004

Acid proteinase has been discovered in Aspergillus niger (acid protease A) and Cryphonectria parasitica (acid proteinase EapC) and it plays major roles in cheese formation from milk. In this study, a partial gene encoding acid proteinase in Penicillium oxalicum HCLF-34 was cloned by using PCR with degenerate primers corresponding to highly conserved regions of the acid proteinase. The partial acid proteinase gene in P. oxalicum HCLF-34 contains an open reading frame of 438 base pairs and encodes an acid proteinase protein of 146 amino aicds. The predicted amino acid sequences showed 71 % homology with acid protease A and 67% homology with EapC.

• Journal of Microbiology and Biotechnology
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• v.21 no.2
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• pp.129-135
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• 2011

Cloning and characterization of the gene encoding a solvent-tolerant protease from the haloalkaliphilic bacterium Geomicrobium sp. EMB2 are described. Primers designed based on the N-terminal amino acid sequence of the purified EMB2 protease helped in the amplification of a 1,505-bp open reading frame that had a coding potential of a 42.7-kDa polypeptide. The deduced EMB2 protein contained a 35.4-kDa mature protein of 311 residues, with a high proportion of acidic amino acid residues. Phylogenetic analysis placed the EMB2 gene close to a known serine protease from Bacillus clausii KSM-K16. Primary sequence analysis indicated a hydrophobic inclination of the protein; and the 3D structure modeling elucidated a relatively higher percentage of small (glycine, alanine, and valine) and borderline (serine and threonine) hydrophobic residues on its surface. The structure analysis also highlighted enrichment of acidic residues at the cost of basic residues. The study indicated that solvent and salt stabilities in Geomicrobium sp. protease may be accorded to different structural features; that is, the presence of a number of small hydrophobic amino acid residues on the surface and a higher content of acidic amino acid residues, respectively.

• Natural Product Sciences
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• v.6 no.3
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• pp.117-121
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• 2000

The water extract of the aerial parts of Orostachys japonicus A. Berger showed the inhibitory activity against HIV-1 protease. From the same parts of O. Japanicus, 4-hydroxybenzoic acid, 3,4-dihydroxybenzoic acid, gallic acid and methyl gallate, together with flavonoids, kaempferol, quercetin, kaempferol $3-O-{\beta}-D-glucoside$, kaempferol $3-O-{\beta}-D-galactoside$ and quercetin $3-O-{\beta}-D-glucoside$ were isolated and characterized by spectral data.

• Korean Journal of Food Science and Technology
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• v.13 no.3
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• pp.241-246
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• 1981

A fungal strain which produced high levels of acid protease and amylase was isolated from the atmosphere for application to the manufacture of digestive enzme preparation. This study was carried out to elucidate its microbiological characteristics, environmental conditions for production of the enzymes, and relationships between the enzyme activity and acidity. 1. The isolate was identified as a fungal strain which belonged to Aspergillus niger by the manual of Rafer and Fennel, and was found to be a strain producing high levels of acid protease and amylase. 2. The optimal pH of tile enzymes produced by the strain were: protease, 2.0;, ${\alpha}-amylase$, 4 to 5; and glucoamylase, 3 to 5. 3. The optimal culture conditions for production of the enzymes were: protease (at pH 2.5), 2 to 3 days incubation on wheat bran at $30^{\circ}C$; ${\alpha}-amylase$ and glucoamylase(at pH 3.0), 3 days incubation at $30^{\circ}C$. 4. The production of acid protease and glucoamylase was increased approximately by 20 percent when 2 percent of corn starch was added to the wheat bran medium. 5. The addition of 0.3 percent ammonium sulfate to the wheat bran medium resulted in enhancing the enzyme production, especially of acid prctease.

• Korean Journal of Microbiology
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• v.20 no.3
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• pp.105-112
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• 1982

The strain of Aspergillus, 6368A, producing acid protease showing high activity was isolated from soil, as a result of wide research about mold group. This strain was identified as a species of Aspergillus tubingensis by the investigation of morphological characteristics. The change of the enzyme production under the various media and culture condition was also studied. The optimum pH and stability of crude acid protease are 2.5, 2.0~4.5 and the optimum temeprature and thermal inactivation waas shown $50^{\circ}C,\;55^{\circ}C$, respectively. From the result of the study on the effects of metal ions, it was found that $MnCl_2,\;CoCl_2,\;CuCl_2,\;SrCl_2,\;and\;NiCl_2$ slightly increased the enzyme activity, on the other hand $ZnCl_2,\;CaCl_2,\;MgCl_2,\;SLS,\;and\;KMnO_4$ decreased it.

• Journal of Animal Science and Technology
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• v.62 no.5
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• pp.614-627
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• 2020

During the course of this trial, our team assessed the influence of protease upon the growth performance, the nutrient digestibility, and the expression of growth-related genes and amino acid transporters within the liver, muscle, and small intestines of broilers. During the first step, our team allocated 600 broilers into four dietary treatments for a period of 35 days in order to measure the growth performance and nutrient digestibility of the broilers selected. The separate treatments contained 10 replicates (15 birds per replicate). The treatments were composed of: 1) CON, basal diet; 2) T1, basal diet + 0.03% protease; 3) T2, basal diet + 0.06% protease; and 4) T3, basal diet + 0.09% protease. Next, the broiler chick sample tissue was harvested from the CON and T3 groups in order to conduct gene expression analysis following the feeding trials the broilers underwent. Our team discovered that the broilers fed protease diets possessed increased body weight and an average daily gain, but conversely, had lower feed conversion ratios when their dietary protease levels increased from 0% to 0.09% (p < 0.05). Additionally, significant linear improvements were identified among the nutrient digestibility of dry matter, crude protein, energy, and amino acids within broilers supplied with protease diets when contrasted and compared with broilers supplied with the basal diet (p < 0.05). In addition, the gene expression of the genes IGF1, IGF2, GH, and LEP in the liver, and the genes MYOD1 and MYOG in the breast muscles, was significantly increased after broilers were fed with a protease diet as compared to broilers that subsisted on a basal diet (p < 0.05). Protease supplementation also raised the expression levels within these amino acid transporters: SCL6A19, SLC7A1, SLC7A7, SLC7A2, SLC7A6, SLC7A9, and SLC15A1, located in the small intestine, when compared to the basal diet (p < 0.05). Our results suggest that protease supplementation in their diet improved the growth performance of broilers via an increase in the expression growth-related genes within broiler liver and muscle tissue. In addition, protease supplementation enhanced broiler digestibility via the upregulation of amino acid transporter expression within the small intestine.