• Korean Journal of Food Science and Technology
• /
• v.47 no.6
• /
• pp.772-778
• /
• 2015

Hydrolysis of isolate soybean protein (ISP) using subcritical water (SCW) was conducted to study the feasibility for producing protein hydrolyzate. SCW hydrolysis of SPI suspension (5-15%) was conducted in an electrically heated batch reactor (2 L). The effects of temperature (230 to $270^{\circ}C$) and holding time (10 to 50 min) on the degree of hydrolysis (DH) and the production of amino acids were studied by surface response method. The DH was determined by derivatizing the hydrolyzates with ortho-phthalaldehyde (OPA) solution. It was confirmed that reaction temperature and holding time affected the hydrothermolysis of soybean protein. However, the holding time was less effective on amino acid yield when the temperature was higher than $230^{\circ}C$. In order to achieve optimal yields of amino acids exceeding 43%, the temperature should be within the range between 256 and $268^{\circ}C$ with holding time from 29 to 41 min, respectively. A maximum estimated amino acid yield of 43.5% was obtained at $268^{\circ}C$ for 35 min.

• Korean Journal of Food Science and Technology
• /
• v.47 no.3
• /
• pp.299-305
• /
• 2015

The Folin-Denis assay using the Folin-Ciocalteu (F-C) reagent has been commonly used for analyzing the total phenolic compound content in various food products. In the present study, the effects of proteins on the reactivity of the F-C reagent with different phenolic compounds were investigated. Bovine serum albumin (BSA) or skim milk proteins showed a concentration-dependent increase in color response in the Folin-Denis assay; these proteins decreased the color response of most phenolic compounds tested. The reactivity of phenolic compounds was significantly less pronounced in the presence of BSA and this interference was greater at higher concentrations of phenolic compounds. The reactivity of phenolic compounds with the F-C reagent was reduced significantly by their oxidation; the reaction of the oxidized products with the F-C reagent was more severely affected by BSA. The interfering effects in the Folin-Denis assay might be attributable to binding interactions of phenolic compounds with proteins.

• Parasites, Hosts and Diseases
• /
• v.34 no.2
• /
• pp.135-142
• /
• 1996

Antigenic domain of jai or surface protein (p30) of Toxoplosmc Sondii was analyzed after polymerase chain reaction (PCR) of its gene fragments. Hydrophilic or hydrophobic moiety of amino acid sequences were expressed as glutathione S-transferase (G57) fusion proteins. Fragments of p30 gene were as follows: 737, total p30 open reading frame (ORF) ; S28, total ORF excluding N-terminal signal sequence and C-terminal hydrophobic sequence; Al9, N-terminal 2/3 parts of A28; A19, N-terminal 2/3 of S28; P9, C-terminal 2/3 part of S28; Z9. middle 1/3 of S28; and 29, C-terminal 1/3 of S28. respectively. Primer of each fragment was synthesized to include clamp sequence of EcoR I restriction site. PCR amplified DNA was inserted info GST (26 kDa) expression vector, PGEX-47-1 to transform into Escheri,hia coei (.JM105 strain). G57 fusion proteins were expressed with IPTG induction as 63. 54, 45, 45, 35, 36. and 35 kDa proteins measured by SDS-PAGE. Each fusion protein was confirmed with G57 detection kit. Western blot analysis with the serum of a toxoplasmosis patient revealed antigenicity in proteins expressed by T37. S28, and Al9 but not those by Pl8. X9, Y10, and Z9. Antigenicity of p30 seems to be located either in N-terminal 115 part in the presence of middle 1/3 part or in the oligopeptides between margins of the first and second 1/3 parts.

• Clinical and Experimental Pediatrics
• /
• v.46 no.8
• /
• pp.758-762
• /
• 2003

Purpose : Our examination was designed to determine the diagnostic properties of the cutoff point for the prediction of bacteremia in febrile children less than 3 years of age. Cutoff point is the value that simultaneously maximizes both sensitivity and specificity. Methods : We conducted a retrospective study of febrile children, less than 3 years of age, who clinically have no identifiable source of fever. Peripheral blood leukocyte count(WBC), absolute neutrophil count(ANC), erythrocyte sedimentation rate(ESR) and C-reactive protein(CRP) were measured at the same time. All patients received blood culture, urine culture and/or CSF culture. Bacterial infection was defined as single pathogen isolated from the CSF or blood or a urinary tract infection (UTI). Patients were dichotomized into two groups : those with bacterial infection and no bacterial infection. We analyzed the characteristics of the children in the two groups. Results : Seventy-one patients(44 males; 27 females) were enrolled in the study. Twenty patients (28%) had a serious bacterial infection(twelve urinary tract infection, five bacteremia, three meningitis) and fifty-one(72%) had no serious bacterial infection. WBC, ESR and CRP were significantly different between the two groups(P<0.05). The cutoff point of WBC, ESR and CRP were $20,000/mm^3$, 30 mm/hr and 3.0 mg/dL, respectively. The sensitivity and specificity of each cutoff point were WBC(75%, 75%), ESR(79%, 68%) and CRP(83%, 77%), respectively. Conclusion : These data show the ability of predictors to identify febrile children less than 3 years of age with bacterial infection. Febrile children who reach the cutoff point must be treated intensively and those who do not reach the cutoff point can be carefully managed without administering antimicrobial agents.

• Biomedical Science Letters
• /
• v.4 no.1
• /
• pp.35-42
• /
• 1998

The effects of CRP purified from human ascites fluid on phagocytic activity of the human macrophage were investigated. CRP was purified using affinity chromatography including absorption on p-diazonium phosphocholine or C-polysaccharide coupled sepharose 4B and gel filtration on hydroxylapatite column chromatography. Macrophage was separated ficoll hypaque gradient density and absorption method, and then was confirmed phagocytic uptake test using latex method. CRP was able either to inhibit or to enhance phagocytic activity of human macrophage against bacteria in vitro. The effects of CRP on phagocytic activity of human macrophage were in time and dose-dependent manners. The additional sequence of reaction mixture against bacteria in vitro shows a threshold stimulus on the activation of phagocytic response upon the CRP.

• The Journal of Korean Society of Virology
• /
• v.27 no.2
• /
• pp.105-113
• /
• 1997

The truncated $E1_{192-283}$ and $E2_{384-649}$ genes of hepatitis C virus (HCV) linked to the gene for glutathione S-transferase (GST) were constructed and their expressions were analyzed. The $GST-E1_{192-283}$ fusion gene overexpressed the fusion protein in E. coli as a soluble form, while the $GST-E1_{192-383}$ plasmid did not express expected fusion protein. The purified $GST-E1_{192-283}$ fusion protein was efficiently cleaved by thrombin. More than 90% pure, HCV $E1_{192-283}$ protein was obtained by GST-agarose chromatography. The truncated $GST-E2_{384-649}$ fusion gene expressed the fusion protein mainly as an insoluble form, whereas the $GST-E2_{384-740}$ did not express the fusion protein. The truncated $GST-E1_{182-283}$ and $GST-E2_{384-649}$ fusion proteins reacted specifically with an HCV patient serum. In addition, mice immunized with either the purified $E1_{192-283}$ or $GST-E2_{384-649}$ proteins generated specific antibodies to each antigen. The results suggested that hydrophobic carboxyl portions of the E1 and E2 proteins might affect expression levels as well as the solubility of each fusion protein in bacteria. Also, the truncated E1 protein with Tyr-192 to Ser-283 contained antigenic epitope(s) which could be specifically recognized by an HCV patient serum.

• Korean Journal of Microbiology
• /
• v.47 no.1
• /
• pp.14-21
• /
• 2011

Riboflavin synthase catalyzes the formation of one molecule of each riboflavin and 5-amino-6-ribitylamino-2,4-pyrimidinedione by the transfer of a 4-carbon moiety between two molecules of the substrates, 6,7-dimetyl-8-ribityllumazine. The most remarkable feature is the sequence similarity between the N-terminal half (1-97) and the C-terminal half domain (99-213). To investigate the structure and fluorescent characteristics of the N-terminal half of riboflavin synthase (N-RS) in Escherichia coli, more than 10 mutant genes coding for the mutated N-terminal domain of riboflavin synthase were generated by polymerase chain reaction. The genes coding for the proteins were inserted into pQE vector designed for easy purification of protein by 6X-His tagging system, expressed, and the proteins were purified. Almost all mutated N-terminal domain of riboflavin synthases bind to 6,7-dimethyl-8-ribityllumazine and riboflavin as fluorescent ligands. However, N-RS C47D and N-RS ET66,67DQ mutant proteins show colorless, indicating that fluorescent ligands were dissociated during purification. In addition, most mutated proteins show low fluorescent intensity comparing to N-RS wild type, whereas N-RS C48S posses stronger fluorescent intensity than that of wild type protein. Based on this result, N-RS C48S can be used as the tool for high throughput screening system for searching for the compound with inhibitory effect for the riboflavin synthase.

• Microbiology and Biotechnology Letters
• /
• v.16 no.6
• /
• pp.526-531
• /
• 1988

Procedure for the purification of pretense from culture broth of Streptomyces sp. SMF301 was developed. It was evident that the strain produced two different proteases of which molecular weights were estimated to be 23, 500 and 38, 900 dalton. It was found that the optimum pH of the smaller was 9.0 and that of the larger was 1.0. The optimal temperature of the alkaline pretense was 5$0^{\circ}C$ and that of the neutral pretense was much more stable than neutral protease at extreme condition viz. high temperature, and pH.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
• /
• 2004.10a
• /
• pp.375-379
• /
• 2004

Probiotic 활성이 높은 L. acidophilus 30SC의 생존성을 증진시키기 위한 기초자료를 얻고자, 열처리 동안 새로이 발현되는 단백질을 일차원 및 이차원 전기영동을 이용하여 확인하였으며, 세포 모양을 주사전자현미경을 사용하여 관찰하였다. $55^{\circ}C$의 heat shock에는 L. acidphilus 30SC의 사멸이 있는 것으로 나타났다. 나머지 처리구는 $37^{\circ}C$에서 계속 배양한 것과 별다른 차이를 나타내지 않았다. $45^{\circ}C$로 heat shock을 준 경우 $37^{\circ}C$에서 배양한 것과 거의 동일하였다. $55^{\circ}C$에서 15분 heat shock을 준 경우 약 22kDa와 25kDa의 단백질들이 새로이 발현된 것으로 나타났으나, 24 kDa와 27kDa로 추정되는 단백질의 발현정도는 낮았음을 확인하였다. 이차원 전기영동을 실시한 결과, $37^{\circ}C$와 비교할 때 $55^{\circ}C$로 heat shock을 준 경우 새로이 5개의 protein spot을 발견할 수 있었다. 그러나 6개의 단백질 spot은 $55^{\circ}C$ heat shock에서 소실된 것으로 확인되어 추가적인 단백질의 분석이 필요한 것으로 생각되었다.

• Applied Biological Chemistry
• /
• v.42 no.2
• /
• pp.152-155
• /
• 1999

Effects of pH, amino acids, hydrolyzed protein and potassium phosphate on caramelization were investigated for improvement of its reaction rate. The caramelization was performed with starch syrup at $110^{\circ}C$ and the different color functions-metric saturation(Suv), 5-hydroxymethylfurfural (HMF) contents and absorbance at 420 nm were measured. As the pH was raised from 4 to 10, the reaction rate (Suv/hr) was increased by 31.9% along with significant increase in HMF content and absorbances at 420 nm. Among the several amino acids, arginine and glycine were very effective for improvement of caramelization, which may be due to Maillard reaction. When $K_2HPO_4$ were added in different ratio with arginine, glycine, HVP or HAP, the effects of arginine and HAP on thee rate were markedly enhanced while the effects of glycine and HVP were rather reduced.