ISSN:
1750-3841
Quelle:
Blackwell Publishing Journal Backfiles 1879-2005
Thema:
Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
,
Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
Notizen:
Streptococcus faecalis possesses a glycerol ester hydrolase (lipase). The enzyme was purified from cell-free extract by ammonium sulphate precipitation, Sephadex G-25 filtration, acetone fractionation, Sephadex G-75 filtration, ion exchange chromatography on DEAE cellulose, to 140-fold with 30% recovery. The isoelectric point of enzyme was found to be 3.6. Its molecular weight was 20,900. With regards to amino acid content, glutamic acid was present in maximum amounts as compared to other amino acids, while cysteine was present in minimum amounts. Michaelis constant of lipase was 5.0 X 10-3M at pH 7.5 at 40°C. Of the simple triglycerides, tributyrin was hydrolyzed most easily by the enzyme, as compared to tricaproin, tricaprylin and triolein. The relative specificity of purified lipase for natural triglycerides was in the following order: butter oil 〉 olive oil 〉 linseed oil 〉 coconut oil. Maximum enzyme activity with butter oil as substrate, was observed at pH 7.5 at 40°C. The enzyme was stable for 1 month at -18°C and was completely inactivated in 10 min at 90°C. The enzyme was stable at pH levels ranging from 6.0-8.0. Addition of bile salts (0.2%) stimulated enzyme activities.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1111/j.1365-2621.1979.tb09131.x
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