Abstract |
Liver from goats with an inherited deficiency of beta-D-mannosidase appears only partially deficient in beta-mannosidase (40% of normal values) when assayed with synthetic beta- mannoside substrates at pH 5.0. Other tissues such as brain and cultured skin fibroblasts show an almost complete deficiency of beta-mannosidase activity. Fractionation of supernatant solutions of normal goat liver on columns of concanavalin A bound to Sepharose 4B resolved beta-mannosidase into a bound (acidic) form (pH optimum, 5.0 to 5.5) and an unbound (neutral) form (broad pH optimum from 5.0 to 8.0). Both forms were heat-labile, inhibited by sodium taurocholate (0.1%) and insensitive to divalent cations such as zinc. However, only the acid lysosomal) form was able to hydrolyze a Man beta GlcNAc beta [3H]GlcNAc trisaccharide. Comparable fractionation of liver from affected goats revealed normal levels of the unbound (neutral) form but a complete absence of the bound (acidic, lysosomal) form. Fractionation of liver from an obligate heterozygote goat revealed normal neutral and 50% of the acidic. These studies suggest that goat liver contains both lysosomal beta-mannosidase (acidic form; deficient in beta-mannosidosis) and nonlysosomal beta-mannosidase (neutral) activity.
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Authors | G Dawson |
Journal | The Journal of biological chemistry
(J Biol Chem)
Vol. 257
Issue 7
Pg. 3369-71
(Apr 10 1982)
ISSN: 0021-9258 [Print] United States |
PMID | 7061483
(Publication Type: Journal Article, Research Support, U.S. Gov't, P.H.S.)
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Chemical References |
- Isoenzymes
- Mannosidases
- beta-Mannosidase
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Topics |
- Animals
- Goats
- Hydrogen-Ion Concentration
- Isoenzymes
(isolation & purification, metabolism)
- Kinetics
- Liver
(enzymology)
- Mannosidases
(deficiency, isolation & purification, metabolism)
- beta-Mannosidase
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