title: Fourier transform infrared absorption studies on the sulfhydryl groups in heavy meromyosin.
abstract: Infrared absorptions of heavy meromyosin solutions were studied in the frequency range of 2600 cm-1 to 1800 cm-1 with a Fourier transform infrared spectrophotometer. An absorption band characteristic of the stretching vibration of sulfhydryl groups was found at about 2565 cm-1. By comparison with the infrared absorption spectrum of a cysteine solution, the absorption band of sulfhydryl groups in heavy meromyosin showed that the absorption intensity is much stronger, the absorption peak shifts to a lower wavenumber and the width of the absorption band is much broadened. These results indicate that the sulfhydryl groups in heavy meromyosin are strongly hydrogen-bound. The additions of ATP and ADP increased the absorption intensity of the absorption band, suggesting the that hydrogen-bonded structure involving the sulfhydryl groups becomes more strengthened on the binding of ATP and ADP. This indicates that myosin heads change conformation around the sulfhydryl groups during ATP hydrolysis.
mesh_terms: D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D000818:Animals; D005583:Fourier Analysis; D009132:Muscles; D015879:Myosin Subfragments; D011485:Protein Binding; D011817:Rabbits; D013055:Spectrophotometry, Infrared; D013438:Sulfhydryl Compounds / Q000032:analysis
chemical_list: D015879:Myosin Subfragments; D013438:Sulfhydryl Compounds; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate