An enzyme with properties similar to those of beta-N-acetylhexosaminidase S is expressed in the promyelocytic cell line HL-60.
Extracts of the human promyelocytic cell line HL-60 contain a form of beta-N-acetylhexosaminidase that is not retained on columns of benzeneboronate-agarose ('phenylboronate-agarose') and has a pI value lower than that of beta-N-acetylhexosaminidase A. It is clearly distinct from beta-N-acetylhexosaminidase A in its behaviour on DEAE-cellulose columns, and it requires a higher concentration of salt for its elution. This 'extra' form has a higher ratio of activity towards 4-methylumbelliferyl beta-N-acetylglucosaminide 6-sulphate and 4-methylumbelliferyl beta-N-acetylglucosaminide than has beta-N-acetylhexosaminidase A and is less stable when heated at 50 degrees C. It has a pH optimum of 4.5 and is therefore not beta-N-acetylglucosaminidase C. Anti-(human beta-N-acetylhexosaminidase alpha-subunit) serum precipitated both beta-N-acetylhexosaminidase A and the 'extra' form, whereas an anti-(beta-subunit) serum precipitated beta-N-acetylhexosaminidase A but not the 'extra' form. Western blotting and immunodetection of polypeptides derived from the 'extra' form revealed a band corresponding in size to mature alpha-subunits. On the basis of this and of its behaviour on isoelectric focusing, chromatofocusing and its kinetic properties, we conclude that the 'extra' form is composed of alpha-subunits and resembles beta-N-acetylhexosaminidase S, the residual form in Sandhoff's disease.
Emiliani
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C
Dipartimento di Medicina Sperimentale e Scienze Biochemiche, Università di Perugia, Italy.
Beccari
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Tabilio
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Orlacchio
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A
Hosseini
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Stirling
J L
JL
D015153:Blotting, Western; D002845:Chromatography; D002848:Chromatography, DEAE-Cellulose; D002850:Chromatography, Gel; D004355:Drug Stability; D006098:Granulocytes / Q000201:enzymology; D006358:Hot Temperature; D006801:Humans; D007525:Isoelectric Focusing; D007700:Kinetics; D015473:Leukemia, Promyelocytic, Acute / Q000201:enzymology*; D012685:Sepharose / Q000031:analogs & derivatives; D013379:Substrate Specificity; D014407:Tumor Cells, Cultured; D001619:beta-N-Acetylhexosaminidases / Q000302:isolation & purification* / Q000378:metabolism
C035597:phenylboronic acid-sepharose; D012685:Sepharose; D001619:beta-N-Acetylhexosaminidases