Functional changes of dextran-modified alkaline proteinase from alkalophilic Bacillus sp

A serine alkaline proteinase (EC 3.4.21.62) from Bacillus sp. (ALPase I) was modified with the 2,4-dialdehyde derivative of clinical dextran (dialdehyde dextran). The modified preparation was purified using an ion-exchange column and gel filtration. The modified enzyme contained 75% carbohydrate by...

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Published inEnzyme and microbial technology Vol. 16; no. 2; pp. 99 - 103
Main Authors Yamagata, Youhei, Arakawa, Kyoko, Yamaguchi, Megumi, Kobayashi, Mikihiko, Ichishima, Eiji
Format Journal Article
LanguageEnglish
Published Amsterdam Elsevier Inc 01.02.1994
Elsevier Science
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Summary:A serine alkaline proteinase (EC 3.4.21.62) from Bacillus sp. (ALPase I) was modified with the 2,4-dialdehyde derivative of clinical dextran (dialdehyde dextran). The modified preparation was purified using an ion-exchange column and gel filtration. The modified enzyme contained 75% carbohydrate by weight. The isoelectric point (pI) of ALPase I was converted from 8.2 to approximately 5.0 by this modification. The specific activity of the dextran-modified ALPase I was 56% of that of the native enzyme when milk casein was used as a substrate. It also had some superior characteristics: the thermostability of the modified enzyme at pH 10.0 was about 10–15°C higher than that of control. In organic solvents such as n-hexane, benzene, and toluene, the hydrolysis reaction of the modified ALPase I for the fluorogenic substrate, succinyl- l-alanyl- l-alanyl- l-prolyl- l-phenylalanyl-4- methylcoumaryl-7-amide (Suc-Ala-Ala-Pro-Phe-MCA), was several times higher than that of the native. This modification greatly improved the stability of ALPase I against nonionic and anionic surfactants. After exposure to lauryl benzene sulfonate and sodium lauryl sulfonate the modified enzyme retained over 95 and 90% of its activity, respectively, but the native enzyme lost its activity. We conclude that modification of serine proteinases with dialdehyde-dextran might be a useful method for improving enzyme character for enzyme technology.
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ISSN:0141-0229
1879-0909
DOI:10.1016/0141-0229(94)90070-1