Optical Activity of Cystine-containing Proteins

Chiroptical properties of proteins. I. Near-ultraviolet circular dichroism of ribonuclease S

“…Similar CD data have been reported for RNase A. 10,11 There is a small positive Cotton effect at 241 nm at pH values from 4.2 to 6.95. A magnitude of 25 deg cm2/dmol was observed at the extremum of this band.…”

Study of protein topography with flash photolytically generated nonspecific surface-labeling reagents: surface labeling of ribonuclease A

“…The CD spectrum of RNase A before and after irradiation is shown in Figure 2. The spectrum of native RNase A is in substantial agreement with that of Pflumm and Beychok (1969) over the entire range of 200-340 nm. The CD of flashed RNase A differs from that of the native enzyme primarily above 235 nm.…”

“…The CD of flashed RNase A differs from that of the native enzyme primarily above 235 nm. The negative band at 275 nm in native RNase A is attributed to contributions from tyrosyl residues and disulfide bonds (Pflumm and Beychok, 1969;Horwitz et al, 1970). The positive band at 242 nm has been ascribed by Simons et al (1969) to "buried" tyrosines.…”

Comparative study on the structure and stability of bovine seminal ribonuclease, its monomeric bis(S-carboxymethylated-31,32) derivative, and bovine pancreatic ribonuclease

“…A distinct feature of the near-ultraviolet CD spectrum of seminal RNase involves the negative ellipticity shown near 242 nm, where both the other two protein molecules show a positive extremum. The positive peak at 242 nm observed with bovine pancreatic RNase A has been attributed to a contribution of exposed tyrosine residues (Pflumm & Beychok, 1969;Simons & Blout, 1968;Simons et al, 1969;Puett, 1972;Strickland, 1972). Rat pancreatic ribonuclease, where the tyrosine residues located at positions 73 and 76 (both exposed) in bovine pancreatic RNase A are missing, does not have a positive ellipticity near 242 nm (Klee & Streaty, 1970).…”