title: Direct observation of substrate distortion by triosephosphate isomerase using Fourier transform infrared spectroscopy.
abstract: The infrared spectrum of dihydroxyacetone phosphate bound to triosephosphate isomerase has been measured. There are two carbonyl bands corresponding to the bound substrate, with an intensity ratio of about 3:1. Relative to the carbonyl absorption of dihydroxyacetone phosphate in free solution, the major band is shifted by 19 cm-1 to 1713 cm-1, providing direct evidence of enzyme-induced distortion of the substrate. This strain is probably attributable to an enzymic electrophile that polarizes the carbonyl group of the substrate and thereby promotes catalysis.
mesh_terms: D000818:Animals; D002238:Carbohydrate Epimerases / Q000378:metabolism; D002645:Chickens; D004099:Dihydroxyacetone Phosphate; D005583:Fourier Analysis; D009132:Muscles / Q000201:enzymology; D011487:Protein Conformation; D013055:Spectrophotometry, Infrared; D014305:Triose-Phosphate Isomerase / Q000378:metabolism; D014306:Trioses
chemical_list: D014306:Trioses; D004099:Dihydroxyacetone Phosphate; D002238:Carbohydrate Epimerases; D014305:Triose-Phosphate Isomerase