Bovine galactosyltransferase: interaction with alpha-lactalbumin and the role of alpha-lactalbumin in lactose synthase.
Bovine alpha-lactalbumin has been dansylated to give an enzymatically fully active, highly fluorescent derivative. This derivative is uniquely labeled on the N-terminal glutamic acid residue of alpha-lactalbumin. This fluorescent derivative of alpha-lactalbumin has been covalently cross-linked to galacto-syltransferase by using dimethyl pimelimidate. Resonance energy transfer measurements using cobalt bound to the transferase as the acceptor of energy transfer from the dansyl group on the alpha-lactalbumin indicate that the dansyl group is 32 A from the cobalt of the transferase. A model of the active site of the transferase and its interaction with alpha-lactalbumin is proposed on the basis of these and previous studies.
D000818:Animals; D002417:Cattle; D002850:Chromatography, Gel; D003619:Dansyl Compounds / Q000378:metabolism*; D007700:Kinetics; D007768:Lactalbumin / Q000031:analogs & derivatives / Q000378:metabolism*; D007788:Lactose Synthase / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D014531:Uridine Diphosphate Galactose / Q000378:metabolism; D014532:Uridine Diphosphate Glucose / Q000378:metabolism
D003619:Dansyl Compounds; D014531:Uridine Diphosphate Galactose; C028373:dansyl alpha-lactalbumin; D007768:Lactalbumin; D007788:Lactose Synthase; D014532:Uridine Diphosphate Glucose