Multiple Forms of Alpha-Galactosidase of the Mouse and Their Use as a Cell Marker in Tumorigenesis2
| Autor: | K. Bruce Jacobson, Jack E. Tobler |
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| Rok vydání: | 1978 |
| Předmět: | |
| Zdroj: | JNCI: Journal of the National Cancer Institute. 61:1263-1268 |
| ISSN: | 1460-2105 0027-8874 |
| DOI: | 10.1093/jnci/61.5.1263 |
| Popis: | cap alpha..-galactosidase was examined as a possible biochemical marker for study of cellular kinetics of tumorigenesis in the mouse ((101 x C3Hf)F/sub 1/ x (C57BL/6RL x SEC/RL)F/sub 1/). Enzyme activity was present in all tissues examined and was maintained in high, constant amounts in adult tissues. Multiple forms of ..cap alpha..-galactosidase were isolated, one set by preparative gel electrophoresis and another by ion exchange chromatography. The two electrophoretic forms (the faster and the slower) compared with respect to their pH optima, K/sub m/ (Michaelis constant), heat stabilities, and inhibitor sensitivities were found to be indistinguishable by these characteristics. Inasmuch as neuraminidase treatment removed the electrophoretic difference, these two forms probably represented posttranscriptional modifications of the main form of ..cap alpha..-galactosidase. DEAE-cellulose (DE-52) chromatography, however, resolved at least two major forms (peak I and peak II) that were independent of the electrophoretic forms. Peak I was unstable to electrophoresis and sensitive to pH changes and heat, had a high K/sub m/ for the artificial substrate 4-methylumbelliferyl-..cap alpha..-D-galactoside, and was different from peak II by these criteria. Gel filtration experiments indicated that peak I could exist as proteins of 29,000 and 52,000 molecular weights, whereas peak II was observed to have amore » molecular weight of 125,000. Attempts to interconvert the two chromatographic forms failed. Possibly, peaks I and II are unrelated structurally and represent two different enzymes.« less |
| Databáze: | OpenAIRE |
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