• 한국축산식품학회지
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• 제42권3호
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• pp.441-454
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• 2022

This study aimed to determine the effect of enzyme, guar gum, and pressure processing on the digestibility and physicochemical properties of age-friendly liver sausages. Liver sausages were manufactured by adding proteolytic enzyme (Bromelain) and guar gum, and pressure-cooking (0.06 MPa), with the following treatments: control, without proteolytic enzyme; T1, proteolytic enzyme; T2, proteolytic enzyme and guar gum; T3, pressure-cooking; T4, proteolytic enzyme and pressure-cooking; T5, proteolytic enzyme, guar gum, and pressure-cooking. The pH was high in the enzyme- and pressure-processed groups. The pressure-processed groups had lower apparent viscosity than other cooking groups, and it decreased during enzyme treatment. Hardness was lower in the enzyme- and pressure-processed groups than in the control, and the T4 was the lowest. Digestibility was the highest in T4 at 82.58%, and there was no significant difference with that in T5. The general cooking group with enzyme and guar gum also showed higher digestibility than the control (77.50%). As a result of the sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the enzyme- and pressure-treated groups (T4, T5) were degraded more into low-molecular-weight peptides (≤37 kDa) than the control and other treatments. Viscoelasticity showed similar trends for viscous and elastic moduli. Similarly, combined pressure processing and enzymatic treatment decreased viscoelasticity, while guar gum increased elasticity but decreased viscosity. Therefore, the tenderized physical properties and improved digestibility by enzyme and pressurization treatment could be used to produce age-friendly spreadable liver sausages.

• BMB Reports
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• 제36권4호
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• pp.390-398
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• 2003

The CDP/Cux transcription factor was previously shown to be proteolytically processed at the G1/S transition. In view of characterizing and eventually identifying the protease responsible for CDP/Cux processing, we have established an in vitro proteolytic processing assay. CDP/Cux recombinant proteins expressed in mammalian or bacterial cells were efficiently processed in vitro using as a source of protease either whole cell extracts, the nuclear or the cytoplasmic fraction. Processing was found to take place optimally at a lower pH, to be insensitive to variations in salt concentration, and to be inhibited by the protease inhibitors MG132 and E64D. Interestingly, the bacterially-produced substrate was more efficiently processed than the substrate purified from mammalian cells. Moreover, processing in vitro was more efficient when CDP/Cux substrates were purified from populations of cells enriched in the S phase than in the G1 phase of the cell cycle. Altogether, these results suggest that post-translational modifications of CDP/Cux in mammalian cells inhibits processing and contributes to the cell cycle-dependent regulation of processing. The in vitro processing assay described in this study will provide a useful tool for the purification and identification of the protease responsible for the processing of CDP/Cux.

• 한국축산식품학회지
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• 제41권4호
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• pp.589-607
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• 2021

Meat proteolytic systems play a crucial role in meat tenderisation. Understanding the effects of processing technologies and post-mortem storage conditions on these systems is important due to their crucial role in determining the quality characteristics of meat and meat products. It has recently been proposed that tenderisation occurs due to the synergistic action of numerous endogenous proteolytic systems. There is strong evidence suggesting the importance of μ-calpain during the initial post-mortem aging phase, while m-calpain may have a role during long-term aging. The caspase proteolytic system is also a candidate for cell degradation in the initial stages of conversion of muscle to meat. The role of cathepsins, which are found in the lysosomes, in post-mortem aging is controversial. Lysosomes need to be ruptured, through aging, or other forms of processing to release cathepsins into the cytosol for participation in proteolysis. A combination of optimum storage conditions along with suitable processing may accelerate protease activity within meat, which can potentially lead to improved meat tenderness. Processing technologies such as high pressure, ultrasound, and shockwave processing have been reported to disrupt muscle structure, which can facilitate proteolysis and potentially enhance the aging process. This paper reviews the recent literature on the impacts of processing technologies along with post-mortem storage conditions on the activities of endogenous proteases in meat. The information provided in the review may be helpful in selecting optimum post-mortem meat storage and processing conditions to achieve improved muscle tenderness within shorter aging and cooking times.

• 한국축산식품학회지
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• 제38권1호
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• pp.143-151
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• 2018

The effects of proteolytic enzymes (bromelain and bromelain+papain) and a ginger extract were assessed on collagen content and solubility, thermal shrinkage temperature of connective tissue, pH, cooking loss, drip loss, and Warner-Bratzler shear force (WBSF) of M. pectoralis profundus isolated from the beef brisket cut. Both proteolytic enzymes and ginger extract led to a significant increase in cooking loss and collagen solubility compared with untreated controls. On the other hand, the peak ($T_p$) thermal shrinkage temperature markedly decreased in all treatments compared with those in controls. Samples treated with bromelain, bromelain + papain, and ginger extract showed a significant decrease in WBSF by 36%, 40%, and 37%, respectively, compared with untreated controls. Our findings suggest that ginger extract are useful for post-mortem tenderization of meat containing high levels of collagen, compared to control even though, bromelain and bromelain + papain treatments have higher collagen solubility than ginger extract.

• 생명과학회지
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• 제10권2호
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• pp.218-227
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• 2000

Bone morphogenetic protein 1 (BMP-1) is part of a complex capable of inducing ectopic bone formation in mammals. Studies on TGF-β1 processing and Drosophila dorsal-ventral patterning have focused attention on BMP-1 as important in mediating the biological activity of this bone inducing complex. Herein, the bacterial expression, refolding, purification, and initial characterization of the BMP-1 proteolytic domain (BPD) are described. A semi-quantitative fluorescence-based thin layer chromatography assay was developed to assist in rapidly screening for optimal renaturation conditions. According to a preliminary screen for optimal conditions for the refolding of BPD , a detectable proteolytic activity against a high turnover substrate for astacin, a homologous protease from crayfish was observed. The conditions identified have allowed the expression of sufficient amounts of BPD for the characterization of the protein. Its proteolytic activity exhibits the same cleavage specificity as astacin against seven substrates that were previously synthesized for studying astacin. Furthermore, this activity is inhibited by the metal chelator 1,10-phenanthroline but not by its analogue 1,7-phenanthroline. The collagenase inhibitor Pro-Leu-Gly hydroxamate was found to inhibit both astacin and BPD activity. The results presented in this paper argue that BMP-1 does in fact possess an intrinsic proteolytic activity.

• 한국수산과학회지
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• 제37권4호
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• pp.259-268
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• 2004

Keeping qualities of crude proteases (CP) and fractionated proteases (FP) sedimenting with $30\~80{\%}$ ammonium sulfate from four kinds of fish viscera as a seafood processing waste were examined. Azocaseinolytic activlties (pH 6 and 8) of CP from anchovy (Engraulis japonica), mackerel (Scomber japonicus), bastard flatfish (Pararlichthys olivaceus) and red sea bream (Chysorphys major) were stable without activity loss at $4^{\circ}C$ for 7 months. Activities of NaCP (CP containing $30{\%}$ sodium chloride) on azocasein were approximately $30{\%}$ lower than those of CP. FP activities Increased 3.4-16.1 folds compared to those of CP and NaCP Powdered crude protease (PCP) and fractionated and powdered protease (FPP) containing various sugars (lactose, sucrose, glucose and dextrin) were prepared by freeze drying. Activities of PCP and FPP containing sucrose were higher and more stable than those of PCP and FPP containing other sugars at $30^{\circ}C$ for whole keeping periods. PCP and FPP from mackerel viscera showed the highest proteolytic activity among four kind of fish vlsceras. The Optimum conditions and stabilities of FPP from mackerel viscera were pH 9 and $50^{\circ}C$, and pH 5-10 and $20-45^{\circ}C$, respectively. The results of this study suggest that FPP from seafood processing waste may be used as processing aids.

• 한국동물학회:학술대회논문집
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• 한국동물학회 2000년도 한국생물과학협회 학술발표대회
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• pp.224.1-224
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• 2000

No Abstract, See Full Text

• 대한바이러스학회지
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• 제29권3호
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• pp.183-193
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• 1999

Human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein is synthesized as a 160 KDa precursor, gp160, that is cleaved by a cellular protease to form the gp120 and gp41 subunits. Mammalian expression vectors were designed that are capable of efficient expression of various mutant envelope glycoproteins derived from a molecular clone of HIV-1. To construct these vectors, one type of mutation was made at the gp120-gp41 cleavage site by oligonucleotide-directed mutagenesis. And another mutation was made to change amino acids in the membrane spanning region of HIV-1 gp41 important for membrane anchorage. Next, these two mutations were combined to generate a vector to have double mutations in cleavage site and membrane-spanning region. These mutants were transiently expressed in mammalian cells. The effect of these mutations on envelope glycoprotein synthesis, proteolytic processing and secretion was determined. In addition, cell surface expression and ability of the glycoprotein to induce syncytium formation were examined. This study provides a mammalian expression system that is capable of efficient expression and secretion of soluble gp160.

• Food Science and Biotechnology
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• 제15권4호
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• pp.499-505
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• 2006

Clostridium botulinum spores are widely distributed in nature. Type A and proteolytic type B bacteria produce heat-resistant spores that are primarily involved in most of the food-borne botulism outbreaks associated with low-acid canned foods. Food-borne botulism results from the consumption of food in which C. botulinum has grown and produced neurotoxin. Growth and toxin production of type A and proteolytic type B in canned foods can be prevented by the use of thermal sterilization alone or in combination with salt and nitrite. The hazardousness of C. botulinum in low-acid canned foods can also be reduced by preventing post-process contamination and introducing hazard analysis and critical control point (HACCP) practices during production. Effectiveness of non-thermal technologies such as high pressure processing with elevated process temperatures on inactivation of spores of C. botulinum will be discussed.

• Applied Biological Chemistry
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• 제33권4호
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• pp.330-336
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• 1990

젓갈에서 분리한 단백질분해균을 이용하여 속성 저식염 멸치젓의 제조조건과 저장중의 품질 안정성에 대하여 실험한 결과 저식염 멸치젓의 제조조건은 생멸치 100g에 대해 식염 1%, B. licheniformis p-5균 배양액 20m1($3.2{\times}10^{4}cells/ml$), sodium erythorbate 1%를 첨가한 후 $40^{\circ}C$, pH7.0에서 15시간 진탕배양(45strokes/min)시킨 후 저장성과 풍미를 고려하여 NaCl 3%, KCl 4%, 에탄을 4%(w/v), 마늘 및 생강가루 각각 0.5%씩 첨가하는 것이며, 저장중 휘발성 염기질소는 서서히 증가하였고, 히스타민 함량은 제조 직후 17.6mg/100g으로 위생상 안정하였다. 그리고 첨가된 Bacillus 속이 저장기간 동안 총균수의 상당량을 지배하였으며, 유리 아미노산 함량이 분석된 정미성분의 대부분을 차지하였다. 휘발성 성분중 휘발성산이 젓갈의 냄새에 기여도가 켰으며 다음으로 카르보닐 화합물, 염기의 순이었다.