Description:
The DNA encoding Human ALT is cloned from the human liver cDNA library, harboring the same amino acid sequence as the native cytosolic ALT ananlyzed by Ishiguro er al. r-hALT is expressed as an active holoenzyme in E. coli. r-hALT is purified to homogeneity as judged by SDS-PAGE. r-hALT is indistinguishable from native one in terms of molecular and catalytic properties.
1) Molecular size is 55 kDa on SDS-PAGE and 101 kDa on gel filtration, indicating a homodimer of two identical subunits.
2) Isoelectric Point is 6.5 when measured by isoelectric focusing.
3) Km value is measured to be 20.5 mM for L-Ala, and 0.443 mM for 2-oxoglutarate.
4) r-hALT shows high compatibility to native ALT on serum ALT assay in clinical chemistry tests.
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