Biomedical subjects

A L Roe

Publications and source records attributed to A L Roe.

21 records · Page 2Linked to original sources

PubMed1986

4-Hydroxyphenylpyruvate dioxygenase is an iron-tyrosinate protein.

A resonance Raman investigation into the blue chromophore of 4-hydroxyphenylpyruvate dioxygenase, a non-heme iron enzyme from Pseudomonas P. J. 874, reveals the presence of enhanced vibrations characteristic of tyrosinate coordination to the iron center. The excitation profiles for these features show that they are associated with the 595 nm absorption feature. EPR studies of this enzyme indicate the presence of a high-spin ferric center in a rhombic environment, as evidenced by a signal at g = 4.3 with the correct intensity for the measured iron content. This enzyme thus belongs to the emerging class of iron-tyrosinate proteins.

4-Hydroxyphenylpyruvate Dioxygenase↗

PubMed1984

Evidence for synergistic anion binding to iron in ovotransferrin complexes from resonance Raman and extended X-ray absorption fine structure analysis.

The 2,3-dihydroxybenzoate and thioglycolate complexes of iron(III)-ovotransferrin have been studied with resonance Raman and extended x-ray absorption fine structure spectroscopies, respectively, to obtain evidence for the coordination of the synergistic anion to the iron center. The dihydroxybenzoate complex exhibits resonance-enhanced Raman vibrations arising from both the endogenous tyrosinates and the added dihydroxybenzoate. A comparison of the extended x-ray absorption fine structure spectra of the carbonate and thioglycolate complexes shows a large feature at about 1.95 A assigned to Fe-(O,N) interactions. The latter complex exhibits an added feature at 2.32 A assigned to an Fe-S interaction. These experiments demonstrate that the Lewis base functions in the synergistic anions coordinate to the iron in ovotransferrin.

Conalbumin↗

PubMed1980

Resonance Raman studies of pyrocatechase-inhibitor complexes.

The resonance Raman spectra of native pyrocatechase and its benzoate and phenolate complexes were investigated by using the available lines of an argon and a krypton laser. The data provide evidence for the presence of two distinct tyrosines coordinated to the active-site iron. The two tyrosines exhibit different upsilon CO values which show maximum resonance enhancements at different excitation wavelengths. Moreover, one tyrosine is more susceptible to changes in the active-site environment. Pyrocatechase is the only example thus far among iron-tyrosinate proteins where the tyrosines coordinating the iron are distinguishable.

Benzoates↗