Dual-lifetime referencing (DLR): a powerful method for on-line measurement of internal pH in carrier-bound immobilized biocatalysts

Table 2 Effect of fluorescence labeling of Sepabeads on CCA immobilization

Labeling	Offered protein (mg/g dry carrier)	Bound protein (mg/g dry carrier)	Specific activity of bound CCA^a (U/mg)
Fluorescein	85	68	1.66 ± 0.06
Fluorescein + Ru(dpp)	85	68	1.50 ± 0.09
None	82	64	1.74 ± 0.17

^a Specific activity was measured using the spectrophotometric assay described in Boniello et al. [21]. Experimental conditions were: 40 mM cephalosporin C; 100 mM PPB (pH 8.0); 37°C

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