1986 Fiscal Year Final Research Report Summary
Studies on lysozyme-catalyzed transglycosylation
Project/Area Number |
60560103
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Research Category |
Grant-in-Aid for General Scientific Research (C)
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Allocation Type | Single-year Grants |
Research Field |
応用生物化学・栄養化学
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Research Institution | Kyushutokai University |
Principal Investigator |
TORIKATA Takao Kyushutokai University Faculty of Agriculture, 農学部, 助教授 (00140955)
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Project Period (FY) |
1985 – 1986
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Keywords | Lysozyme / Transglycosylation / 反応機構 |
Research Abstract |
Lysozyme, which is a carbohydrolase, exhibits the high efficiency of transglycosylation. To elucidate the molecular mechanism of transglycosylation, guineahen lysozyme was subjected to a comparative study taking hen lysozyme as reference. <Arg_(114)> in subsite F of hen lysozyme is replaced with <His_(114)> in guinea-hen lysozyme. The experimental time-courses were measured with a substrate of chitopentaose <(GlcNAc)_5> and the values of reaction parameters were estimated from the experimental time-courses by computer analysis. The characteristic of the time-courses of guinea-hen lysozyme was increased the production of <(GlcNAc)_4> at an early stage of the reaction, which may be caused by the slowing down of the rate of transglycosylation. The experimental time-courses were measured at various pHs. It was assumed that pH-dependence of transglycosylation was due to the ionizable state of <His_(114)> . The chemical modification of <His_(114)> in subsite F of guinea-hen lysozyme was attempted with diethylpyrocarbonate (DEP). The experimental time-courses indicated that DEP-lysozyme catalyzed predominantly hydrolysis of substrate, but scarcely transglycosylation. From those results, acceptor molecule and substrate can be speculated to bind to a different position in subsite F. It is presumed that the formation of lysozyme-substrate-acceptor complex results in the high efficiency of transglycosylation.
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