Kurakake Masahiro, Ogawa Kenji, Sugie Motoki, Takemura Akihiro, Sugiura Kouji, Komaki Toshiaki
Faculty of Life Science and Biotechnology, Department of Applied Biological Science, Fukuyama University, Sanzou, Gakuenchou 1 banchi, Fukuyama, Hiroshima 729-0292, Japan.
J Agric Food Chem. 2008 Jan 23;56(2):591-6. doi: 10.1021/jf072762k. Epub 2007 Dec 19.
Aspergillus oryzae KB produces two types of beta-fructofuranosidases, F1 and F2. F1 produces 1-kestose, nystose, and fructosyl nystose from sucrose through its transfructosylation action. F2 hydrolyzes sucrose to glucose and fructose. N-Terminal amino acid sequences of the purified enzymes were DYNAAPPNLST for F1 and YSGDLRPQ for F2. Each enzyme encoding gene was identified in the genome of Aspergillus oryzae. Although the KB strain showed a higher production of F2 than F1 in a low sucrose liquid medium, F2 production gradually decreased, whereas F1 production increased with increasing sucrose concentration in the medium. Synthesis of F1 and F2 mRNAs analyzed on reverse-transcription polymerase chain reaction corresponded to individual enzymatic production. During liquid culture of the KB strain, F1 synthesizes fructooligosaccharides from sucrose through transfructosylation, and F2 gradually hydrolyzes it. In a highly concentrated sucrose medium, intake of sucrose into the KB strain was depressed by F1 through synthesis of transfer products, fructooligosaccharides.
米曲霉KB产生两种β-呋喃果糖苷酶，F1和F2。F1通过其转果糖基化作用从蔗糖产生1-蔗果三糖、蔗果四糖和果糖基蔗果四糖。F2将蔗糖水解为葡萄糖和果糖。纯化酶的N端氨基酸序列，F1为DYNAAPPNLST，F2为YSGDLRPQ。每个酶编码基因在米曲霉基因组中被鉴定。虽然KB菌株在低蔗糖液体培养基中F2的产量高于F1，但F2产量逐渐下降，而F1产量随着培养基中蔗糖浓度的增加而增加。通过逆转录聚合酶链反应分析的F1和F2 mRNA的合成与各自的酶产量相对应。在KB菌株的液体培养过程中，F1通过转果糖基化作用从蔗糖合成低聚果糖，而F2则逐渐将其水解。在高浓度蔗糖培养基中，F1通过合成转移产物低聚果糖抑制蔗糖进入KB菌株。
