• 한국미생물·생명공학회지
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• 제17권2호
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• pp.85-87
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• 1989

토양으로부터 분리한 Xylose 발효효모 X-6-41 (Candida sp.)의 xylanase 효소생성 조건을 조사해 본 결과, 본 실험에 사용한 X-6-41 균주는 배지조성중 yeast extract 혹은 polypeptone이 첨가되면 xylanase 효소생성이 없었다. 즉 특정 아미노산인 isoleucine에 의해서는 그 생성이 억제되었고, tryptophan 25$\mu$g/$m\ell$ 농도의 존재하에서는 xylanase 생성이 증가했다.

• Journal of Microbiology and Biotechnology
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• 제7권5호
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• pp.341-344
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• 1997

Batch cultures of Anacystis nidulans BD-1 resistant to azaleucine and fluorotyrosine produced and liberated a wide range of amino acids, notably glutamic acid, alanine, phenylalanine, leucine, isoleucine, cysteine and methionine. Sustained liberation for prolonged periods was achieved after immobilization on calcium alginate and the net concentration in the medium was 0.18-0.2 g $I^{-1}$. While acetohydroxy acid synthase in azaleucine-resistant mutant lost leucine- and isoleucine-sensitivity, fluorotyrosine-resistant strain turned phenylalanine activating. The activities of nitrate assimilating enzymes were also higher in the mutants and were relaxed from ammonium-repression. The metabolic adjustments involved in amino acid overproduction are discussed.

• BMB Reports
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• 제32권2호
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• pp.210-213
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• 1999

In Serratia marcescens, acetolactate produced by the catabolic acetolactate synthase (ALS) is converted into acetoin, its physiological role of which is to maintain intracellular pH homeostasis. In this study, the expression mode of catabolic ALS by aeration and branched-chain amino acids was examined by the ELISA method. The amount of catabolic ALS decreased approximately 93% under aerobic conditions. We also showed that the expression of catabolic ALS decreased approximately 34 % and 65 % in the presence of 2.5 mM and 10 mM leucine, respectively. The repression of catabolic ALS by leucine has not been reported previously. In contrast to leucine, catabolic ALS levels increased approximately 13% and 38% by treatment with 2.5 mM and 10 mM isoleucine, respectively, while valine alone did not have any significant effect on the synthesis of catabolic ALS. The amount of catabolic ALS was also reduced to approximately 32% and 45% in the presence of 10 mM Leu+Ile and Leu+Ile+Val, respectively. The regulatory mode of the Serratia catabolic ALS suggests that catabolic ALS may also have a role in supplying acetolactate as an intermediate of valine and leucine biosynthesis in addition to the maintenance of internal pH.