Subtilisin enzymes: A note on time‐resolved fluorescence and circular dichroism properties

Abstract
This note briefly corrects previous information about the time‐resolved fluorescence properties of preparations of subtilisin Carlsberg and subtilisin BPN′. We confirm the observation of segmental motion of the single tryptophan in subtilisin Carlsberg by analysis of the time‐resolved fluorescence anisotropy, and present circular dichroism and spectroscopic data on the two proteins. Near‐UV properties clearly differentiate between the two proteins. Far‐UV circular dichroism confirms that the two subtilisins have closely similar secondary structure in solution; the multi‐component analysis is consistent with the established X‐ray conformations, but the quantitative agreement is still somewhat imperfect.