• Applied Biological Chemistry
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• 제38권3호
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• pp.196-201
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• 1995

토양으로부터 분리한 신규의 aminopeptidase M 저해제 MR-387A 및 B를 생산하는 균주 SL-387의 화학동정 및 수리동정을 하였다. 배양학적 및 형태학적 특성과 화학지표에 의하여 분리균주는 Streptomyces에 속하는 것으로 판단되었다. 종의 동정을 위하여 41개 동정 단위형질에 대하여 조사한 후 TAXON 프로그램을 사용하여 수리동정을 하였다. 분리균주는 Streptomyces의 주군집 18에 속하는 균주로 Streptomyces eyagawaensis와 공유도계수($S_{SM}$) 75.6%로 가장 유사 하였다. 이상의 화학동정 및 TAXON 분석에 의하여 분리균주 SL-387은 Streptomyces neyagawaensis이거나 그 유연 균주인 것으로 동정 되었다.

• BMB Reports
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• 제36권5호
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• pp.508-513
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• 2003

The bacterium Bacillus thuringiensis produces toxin inclusions that are deleterious to target insect larvae. These toxins are believed to interact with a specific receptor protein(s) that is present on the gut epithelial cells of the larvae. In various insect species (in particular those belonging to the lepidopteran class), aminopeptidase N (APN) is one of the two receptor proteins that are considered to be involved in toxin-receptor interactions. However, in mosquitoes, the nature and identity of the receptor protein is unknown. Here, using RT-PCR, we identified two isoforms of the APN transcripts in the Aedes aegypti mosquito larval midgut. These results are congruent with a previous report of multiple isoforms of the APN gene expression in lepidopteran larvae. Which of the two isoforms (or other yet unidentified receptor proteins) is involved in the killing of mosquito larvae remains to be elucidated.

• Journal of Microbiology and Biotechnology
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• 제9권6호
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• pp.861-869
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• 1999

An extracellular protease was purified to homogeneity from the culture supernatant of psychrotrophic bacteria Bacillus sp. JH 108 using procedures including ammonium sulfate fractionation, anion exchange chromatography, gel filtration chromatography, and cation exchange chromatography. The enzyme exhibited a molecular weight of 36 kDa, an optimum pH of 8 to 9, and optimum temperature of $60^{\circ}C$. The enzyme preferentially hydrolyzed leucine at the N-terminus of peptides and thus can be classified as an aminopeptidase. It was strongly inhibited by metal chelating agents such as EDTA and l, l0-phenanthroline. The activity lost by EDTA was restored with $Zn^{2+}{\;}or{\;}Co^{2+}$. These divalent cations also stimulated the native enzyme. This suggests that the enzyme is a metalloprotease acting as a leucine aminopeptidase.

• 생명과학회지
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• 제21권5호
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• pp.761-765
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• 2011

효소의 염에 대한 안정성은 식품산업 응용에 있어서 중요한 인자이다. 이전에, leucine aminopeptidase (LAP)은 Bacillus sp. N2에서 정제되었다. 본 연구에서는, LAP효소의 염 효과에 관한 연구를 수행했다. LAP은 고농도의 NaCl (4 M)에서 L-leucine-${\rho}$-nitroanilide의 가수분해활성을 가지고 있지만, 다른 중성 염들(LiBr, LiCl, NaBr, KBr, KCl)에서는 활성이 없었다. 그 효소는 0-4 M NaCl 농도에서 C-말단 Xaa쪽에 소수성 아미노산과 친수성 아미노산을 가진 여러 di-peptide 합성 기질들을 가수분해하였는데, 이러한 결과는 LAP의 가수분해성은 기질의 Scissile bond에 있는 아미노산 사이드 체인의 소수성과는 관련이 없다라는 것을 의미한다. 또한, LAP의 가수분해활성은 4.5 M NaCl 농도에서 다른 LAP와 Aminopeptidase의 활성 보다 1-3배가 높다라는 것을 보여주었다. 이러한 결과들은 NaCl에 내성을 지닌 LAP을 치즈와 멸치 젓갈과 같은 식품 산업에 응용될 수 있다는 것을 보여준다.

• Journal of Microbiology and Biotechnology
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• 제10권5호
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• pp.573-579
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• 2000

Knowledge on the enzymes acting on p-amino-acid-containing peptides appears to be somewhat limited when compared with those acting on peptides composed on L-amino acids. Less than ten D-stereospecific enzymes are hitherto known. This review describes about several novel D-stereospecific peptidases and amidases of microbial origin, including D-aminopeptidase (E.C. 3.4.11.19), alkaline D-peptidase, and D-amino aicd amidase, which are applied to the synthesis of D-amino acid/or D-amino acid derivatives.

• 한국수산과학회지
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• 제54권5호
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• pp.724-732
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• 2021

This study used response surface methodology to investigate the optimal conditions to reduce the bitterness of alcalase-treated anchovy hydrolysate (AAH) by the aminopeptidase active fraction (AAF) derived from the common squid Todarodes pacificus hepatopancreas. The central composite design selected AAF/AAH ratio (X₁, %) and hydrolysis time (X₂, h) as independent variables, and the degree of hydrolysis (Y₁) and bitterness (Y₂) as dependent variables. The uncoded values of the multiple response optimization for independent variables were 3.4% for the AAF/AAH ratio and 9.2 h for the hydrolysis time. The predicted values of the yield and bitterness score of alcalase-AAF continuously treated anchovy hydrolysate (AAAH) under the optimized conditions were 68.9% and 4.6 points, respectively. Their measured values of 69.5% for yield and 4.6±0.5 points for bitterness were similar to the predicted values. The food components of AAAH were 91.4% (moisture), 7.5% (protein), 0.1% (lipid) and 0.6% (ash). The findings indicate the potential value for use as an anchovy seasoning base. The results also confirm that the bitterness of AAH was remarkably improved by AAF and implicates AAF derived from squid hepatopancreas as a good enzyme to catalyze reduced bitterness.

• 한국미생물·생명공학회지
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• 제24권3호
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• pp.336-343
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• 1996

Maximum amount of the aminopeptidase M inhibitors produced by Streptomyces griseoplanus SL20209 in 500 ml-Erlenmeyer flask was accumulated after cultivation for 3 days at 28$\circ$C, thereafter the amount of inhibitors decreased slowly with a pH change to alkaline. Arabinose, xylose, mannose and soluble starch were good carbon sources for the production of the inhibitors. On the other hand, glucose was only good for the cell growth but potently inhibited the production of inhibitors. Natural organic nitrogen sources such as soybean meal, fish meal, gluten meal and peanut powder were good for the production of inhibitors, however, soytone, peptone and inorganic nitrogens such as NH$_{4}$C1 and NH$_{4}$NO$_{3}$ were poor. Inclusion of yeast extract (0.5%, w/v) or K$_{2}$HPO$_{4}$ (0.05%) into the production medium increased the production of inhibitors by accelerating cell growth. The production of inhibitors was slightly increased on the medium containing CaCO$_{3}$ (0.3%) and zeolite (0.5%), respectively. Optimal temperature and initial pH range for the production ot inhibitors were determined to be 28$\circ$C and 6.0-7.0, respectively. Employing two improved production media consisting of 3% arabinose or soluble starch, 2.5% soybean meal, 0.5% yeast extract, 0.05% K$_{2}$HP0$_{4}$, 0.1% CaCO$_{3}$ and 0.3% zeolite (pH 6.8), 1.8-fold increase in the amount of inhibitors was achieved, comparing with the basal medium used.

• Journal of Microbiology and Biotechnology
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• 제5권3호
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• pp.154-157
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• 1995

MRK-22, an inhibitor of aminopeptidase M was isolated from the culture broth of Streptomyces sp. SL20209. The structure of MRK-22 was defined to be 3-amino-2-hydroxy-5-methylhexanoyl-valyl-valine, des-$Asp^4$-amastatin, by spectroscopic analysis and this was also confirmed by solid phase synthesis of the inhibitor. The molecular formula and weight of MRK-22 were $C_17H_33N_3O_5$ and MW 359($M^+$), respectively, and its $IC_50$ value against hog kidney AP-M was 0.79 $\mu$ g/ml.

• Journal of Microbiology and Biotechnology
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• 제5권5호
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• pp.280-284
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• 1995

Aspergi11us niger F-580, a potent producer of aminopeptidase M inhibitor, was isolated from the brown spots of plant leaves with a pathological trait. The inhibitory activity was found only in the fungal mat formed by surface culture of Aspergi11us niger F-580, but not in the culture supernatant or cell pellet. The inhibitor was purified from the hot water extract of this fungal mat by using chromatographies on Diaion HP-20, DEAE-cellulose, Sephadex G-l0 and YMC-ODS-AQ columns. The purified inhibitor was analyzed by UV, mass, and NMR spectroscopies, and identified as OF494911, which had been isolated as an aminopeptidase B inhibitor from Penicillium rugulosum OF4949

• Journal of Microbiology and Biotechnology
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• 제5권1호
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• pp.36-40
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• 1995

Valistatin, a new inhibitor of aminopeptidase M(AP-M) was discovered in the culture broth of Streptomyces sp. SL20209 isolated from a soil sample. The inhibitor was purified by extraction with n-butanol and the various column chromatographies, and then isolated as whitish powder. The $^1 H-and ^1 H, ^1 H-COSY$ NMR studies, amino acid analysis, and fragmentation patterns by FAB-MS suggested the presence of one 3-amino-2-hydroxy-4-phenylbutanoic acid and two valine residues in the inhibitor. Thus, the structure of valistatin was determined as 3-amino-2-hydroxy-4-phenylbutanoyl-valyl-valine. Valistatin has the molecular formular $C_20H_31N_3 O_5$ (MW 394), and its $IC_50$ value against hog kidney AP-M was determined to be 3.12 $mu g/ml$.