• 한국미생물·생명공학회지
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• 제23권1호
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• pp.47-52
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• 1995

Since the original productivity of new aminopeptidase M inhibitors MR-387A and B by Streptomyces sp. SL-387 (KCTC 0102BP) was not enough for further chemical and biological evaluation, mutation of parent strain by the treatment of N-methyl-N'-nitro-N-nitrosoguanidine was performed in order to obtain a clone with greater inhibitory activity. Mutant N-3 was selected due to a 6-fold greater productivity (40 $\mu$g/ml) than that of the wild type(6.7 $\mu$g/ml). This mutant was resistant to 3,4-dehydro-DL-proline, an antimetabolite of proline, with 25 $\mu$g/ml of minimum inhibitory concentration. Furthermore, the characteristic morphological change from spiral spore chain in wild type to straight in mutant was observed. An aminopeptidase M nhibitor different from MR-387A and B was isolated from the culture broth of the mutant. This inhibitor was composed of 2 proline, 1 valine, and an unknown amino acid which is presumably 3-amino-4-phenylbutanoic acid. IC$_{50}$ value (89.1 $\MU$g/ml) of the purified inhibitor was lower than that of other inhibitors, which may be due to the absence of 2(S)-hydroxyl group within the structure of 3-amino-4-phenyl- butanoic acid.

• Applied Biological Chemistry
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• 제38권2호
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• pp.100-105
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• 1995

토양으로부터 분리한 Streptomyces sp. SL-387 균주에 의하여 신규 aminopeptidase M 저해제 MR-387A 및 B를 생산하기 위한 최적 배지 조건을 검토하였다. 최적 배지 조건으로 glucose 1%, soybean meal 3%, yeast extract 0.2%, beef extract 0.1%, NaCl 0.3%, $K_2HPO_4$ 0.01%, $CaCO_3$ 0.03%, $MnCl_2{\cdot}4H_2O$ 0.001%, $ZnCl_2{\cdot}7H_2O$ 0.001%, $MgSO_4{\cdot}7H_2O$ 0.0005%, pH 7.0가 적당한 것으로 나타났다. 이 배지를 발효용 배지로 사용하였을때 저해제의 생산은 배양 120시간에 최대에 도달하였으며, 그때의 최대 생산성(total productivity)은 909.1 U/ml이었다.

• 한국미생물·생명공학회지
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• 제22권5호
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• pp.447-452
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• 1994

The strain SL-387 which produces new inhibitors of aminopeptidase M, MR-387A and B, was isolated from a soil sample. The strain has branched substrate mycelia, from which aerial hyphae develop in the form of open spirals. Spore surface is smooth. Melanoid and soluble pigme- nts were observed. The isolate contains LL-diaminopimelic acid in its cell wall hydrolysate, and has no pectinolytic activity. The strain SL-387 is closely related to Streptomyces griseoruber and S. naganishii, but is different from these strains in some cultural and physiological characteristics. This strain was, therefore, designated as Streptomyces sp. SL-387. The effects of several carbon and nitrogen sources on the production of the inhibitor were examined. Among them, glucose, galactose, mannose, and xylose were effective as a carbon source and soybean meal, soytone, fish meal, and gluten meal were effective as a nitrogen source. The maximum peak of the inhibitor production in jar fermentor was obtained on the fifth day of culture.

• Journal of Microbiology and Biotechnology
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• 제5권3호
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• pp.158-162
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• 1995

The effect of carbon and nitrogen sources on the production of novel aminopeptidase M inhibitors MR-387A and B by Streptomyces sp. SL-387 has been studied. High D-glucose and ammonia concentrations (5$\%$ and 1$\%$, respectively) exerted a negative influence on the inhibitor formation. The suppressive effect of glucose on the inhibitor formation is probably caused by an effect of medium pH rather than that of cyclic AMP. To establish the optimum conditions for inhibitor overproduction, various nitrogen sources and ammonium ion-trapping agents were examined. The use of ammonia slow-releasing nitrogen sources such as soybean meal and fish meal, or ammonium ion-trapping agents such as kaoline, celite, and natural zeolite achieved the enhancement of inhibitor production. These results also indicate that inhibitor formation is affected by ammonium ion repression.

• Journal of Microbiology and Biotechnology
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• 제5권4호
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• pp.213-217
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• 1995

The effect of inorganic phosphate on the fermentative production of aminopeptidase M inhibitors MR-387A and B by Streptomyces sp. SL-387 has been studied. With inorganic phosphate concentrations higher than 0.78 mM, an inverse correlation was found between the maximum inhibitor production and the initial phosphate concentration added. Growth sensitivity of this actinomycete to arsenate, a phosphate analogue, and the use of magnesium carbonate, a phosphate-trapping agent, suggested that the inhibitor formation was under phosphate repression. Exogenous ATP further increased the degree of phosphate interference in both phosphate-repressed and non repressed culture conditions. The use of a phosphate analogue and a protein synthesis inhibitor also suggested that the phosphate itself repressed inhibitor formation.