We have characterized the influence of protein–carbon nanotube interactions on protein structure and function using various techniques such as Fourier transform infrared spectroscopy, circular dichroism spectroscopy, and atomic force microscopy. This structure-based analysis revealed that different proteins interact with nanotubes differentially, consistent with the observed biological activity data. Furthermore, the high degree of surface curvature of the nanoscale support was found to play an important role in stabilizing proteins under denaturing conditions. Along with these fundamental studies, various applications of such highly active and stable nanotube–protein conjugates have been pursued, which include self-cleaning nanobiocomposite films, interfacial biocatalysis in a biphasic medium, and synthesis of nanotube–nanoparticle hybrids, among others.