Xin Vector Labs is a company that specialise in avidin/biotin systems and lectins. I've used their avidin/biotin products and they've been good, so is their technical support. Their address is US 30 Ingold Road Burlingame CA 94010 Tel: (415) 697 3600 UK 16 Wulfric Square Bretton Peterborough PE3 8RF Tel: 0733 265530 Amanda