Abstract
A neutral beta-galactosidase has been purified by concanavalin A-Sepharose affinity chromatography, DEAE-cellulose chromatography, Sephadex G-200 gel filtration and hydroxylapatite chromatography. The enzyme was purified 126-fold with a yield of about 21%. This form has a neutral optimal pH (7.5) and it is located in the cytosolic fraction. It shows a wide pH stability from pH 4.5 to 8.0, but it is very unstable at low pH values. Its isoelectric point is 4.9 and this value does not change on neuraminidase treatment. The estimated molecular weight was 47 000. The neutral form shows beta-D-galactosidase, beta-D-fucosidase and beta-D-glucosidase activities, all of them associated in a single peak in all the purification steps. p-Nitrophenyl beta-D-galactosides, p-nitrophenyl beta-D-fucosides and p-nitrophenyl beta-D-glucosides competed fully for a common active site in mixed-substrate experiments. Using gamma-D-galactonolactone as competitive inhibitor the Ki values were always coincident for the three activities. The effect of NaCl, methyl mannoside and some sugars (fucose, galactose and glucose) was studied.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
