α-Lactalbumin Induces Bovine Milk β1,4-Galactosyltransferase to Utilize UDP-GalNAc (∗)
We now report that α-lactalbumin (α-LA) has a novel effect on bovine milk UDP-Gal:GlcNAc-β1,4-galactosyltransferase (β1,4-GT) and induces the enzyme to efficiently utilize UDP-GalNAc as a donor. In the presence of α-LA the enzyme transfers GalNAc to free GlcNAc to produce GalNAcβ1-4GlcNAc at a rate...
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Veröffentlicht in: | The Journal of biological chemistry 1995-08, Vol.270 (31), p.18447-18451 |
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Hauptverfasser: | , , |
Format: | Artikel |
Sprache: | eng |
Online-Zugang: | Volltext |
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Zusammenfassung: | We now report that α-lactalbumin (α-LA) has a novel effect on bovine milk UDP-Gal:GlcNAc-β1,4-galactosyltransferase (β1,4-GT) and induces the enzyme to efficiently utilize UDP-GalNAc as a donor. In the presence of α-LA the enzyme transfers GalNAc to free GlcNAc to produce GalNAcβ1-4GlcNAc at a rate 55% of that compared to the rate when UDP-Gal is the donor in the absence of α-LA. The stimulation by α-LA is dependent on the concentrations of α-LA, acceptor, and sugar nucleotide. Interestingly, β1,4-GT is unable to transfer GalNAc to Glc with or without α-LA. α-LA also stimulates the transfer of GalNAc from UDP-GalNAc to various chitin oligomers, although the degree of stimulation decreases as the acceptor size increases. Thus, bovine milk β1,4-GT has an inherent ability to utilize two different sugar nucleotides and the sugar nucleotide preference is regulatable by α-LA. |
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ISSN: | 0021-9258 1083-351X |
DOI: | 10.1074/jbc.270.31.18447 |