ISSN:
0377-0486
Keywords:
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
A new technique is described for the study of intermediates formed in enzyme-substrate complexes by resonance Raman spectroscopy. This technique uses an ultraviolet line from a YAG laser which is obtained by frequency doubling to 266 nm and then shifting by means of stimulated anti-Stokes Raman scattering to 239 nm. The advantage of this line is that it falls in an absorption minimum for the aromatic residues, tyrosine and tryptophan, which permits the observation of resonance Raman spectrum of enzyme-substrate intermediates whose absorption maxima fall within the range 225-245 nm. In order not to decompose the sample and yet conserve it, a slow flow technique has been devised which avoids the use of a quartz window. The method is illustrated with the complex formed from a simple oligopeptide and the enzyme papain. Excellent ultraviolet resonance Raman spectra are obtained from the enzyme, the substrate and the complex. By computer subtraction of the component spectra from the spectra of the complex, the presence of a new band at 1680 cm-1 is seen, which is ascribed to the carbonyl band of the acyl group bound at the active site.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jrs.1250180312
