© 1996 Oxford University Press
research-article |
Binding of Acrylonitrile to Parvalbumin



*Departments of Pharmacology and Toxicology, Protein/Nucleic Acid Shared Facility, Medical College of Wisconsin 8701 Watertown Plank Road, Milwaukee, Wisconsin 53226, West Paterson, New Jersey
Departments of Gytec. inc., Protein/Nucleic Acid Shared Facility, Medical College of Wisconsin 8701 Watertown Plank Road, Milwaukee, Wisconsin 53226, West Paterson, New Jersey
Departments of Biochemistry, Protein/Nucleic Acid Shared Facility, Medical College of Wisconsin 8701 Watertown Plank Road, Milwaukee, Wisconsin 53226, West Paterson, New Jersey
Received April 24, 1995; accepted August 22, 1995
A previous study has shown that acrylonitrile (ACN) has a long half-life in rainbow trout muscle and that [14C]ACN appears to be bound to a 10,000-Da protein in muscle. The labeled protein was purified from muscle of trout exposed to [14C]ACN, separated on 20% SDSPAGE, and digested for amino acid analysis and sequence analysis. These studies indicated that the labeled protein was the Ca2+-binding protein parvalbumin. Parvalbumin is an important calcium-binding protein thought to be involved in the regulation of calcium levels in various parts of the body ranging from neurons to fast-twitch muscle contractions. To study the reaction between parvalbumin and [14C]ACN, frog parvalbumin was incubated with [14C]ACN in vitro under various conditions. These studies indicated that the maximum labeling occurred at 1 nmol/nmol parvalbumin and at pH 7. Amino acid analysis of the labeled protein indicated that the labeled amino acid was probably histidine, and endoproteinase Glu-C (V-8) digestion studies revealed that the 14C was in the 181 amino acid segment of the protein, an area that contains two histidines.