Raean Spectrum of Protocatecbuate Dioxygenase from Psevdomonas Pvtida

The Raman spectrum (441.6 nm excitation) of protocatechuate 3,4dioxygenase (PCD) from Pseudmionas putida shows resonance enhanced bands at 1605, 1504, 1270, 858, and 830 cm-1 which are due to the p-hydroxyphenyl group of tyrosine coordinated to iron. In addition, we observe strong resonance enhanced bands at 592 and 524 cm-' and weak (presumably iron1igand)vibrations at 465, 423, and 371 cm-l. Recent publications of the Raman spectrum of PCD from Pseudomonas aerugirwsa (Tatsuno et al J. Am. Chem. -' Sot. 100, 4614-4615 (1978) and Keyes et al Biochem. Biophys. Re8. Cornn. 83, --' 941-945 (1978) using 488 and 514 nm excitation did not report these bands. Cur 441.6 nm excitation Raman spectrum of human serum transferrin, another metalloprotein with an iron-tyrosine linkage, does not show the 592 and 524 cm-l bands and has only two very weak bands at about 423 and 364 cm-l. We discuss several interpretations of these data.