The Penicillium chrysogenum transporter PcAraT enables high-affinity, glucose-insensitive l-arabinose transport in Saccharomyces cerevisiae

Table 4 Kinetic data for the S. cerevisiae transporter Gal2 and P. chrysogenum PcAraT derived from uptake studies with ¹⁴C-labelled l-arabinose, d-glucose and d-xylose. Sugar transport kinetics were measured by uptake of ¹⁴C-radiolabelled sugars by S. cerevisiae DS68625, an engineered strain lacking the Hxt1-7 and Gal2 transporters, expressing either GAL2 or PcaraT

	Gal2	PcAraT
K_{m, ARA} (mmol L⁻¹)	335 ± 21	0.13 ± 0.03
V_{max, ARA} [nmol (mg biomass)⁻¹ min⁻¹]	75 ± 5.2	5.3 ± 0.2
K_{m, GLC} (mmol L⁻¹)	1.9	–
V_{max, GLC} [nmol (mg biomass)⁻¹ min⁻¹]	26	–
l-Arabinose transport inhibition by glucose	85%	63%
K_{m, XYL} (mmol L⁻¹)	226 [20]	–
V_{max, XYL} [nmol (mg biomass)⁻¹ min⁻¹]	91 [20]	–
l-Arabinose transport inhibition by d-xylose	29%	22%

Transport inhibition was determined at 50 mmol L⁻¹ [¹⁴C] l-arabinose and 100 mmol L⁻¹ of either d-glucose or d-xylose and expressed relative to the transport rate observed in the absence of d-xylose or d-glucose. Values are represented as average ± mean deviation of duplicate experiments. Graphs used to calculate kinetic parameters are shown in Additional files 3–6. ARA, l-arabinose; GLC, d-glucose; XYL, d-xylose; –, no transport

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