CHED 219 |
| The physiological properties of muscles, such as contraction and relaxation, are highly dependent on isoforms of various muscle proteins. Different muscle fiber types display different physiological properties due to variations in the isoform(s) of myosin, troponin and other myofibrillar proteins. Parvalbumin, a myoplasmic protein with two isoforms, is a low molecular weight protein (9-11 kD) that appears to aid in relaxation. It does so by binding to free Ca2+, which reduces the intracellular concentration of the ion. Since calcium plays a necessary role in contraction by binding to the regulatory protein troponin, a decrease in its intracellular concentration will result in relaxation of the muscle fiber. For parvalbumin to bind Ca2+, Mg2+ must not be bound. Furthermore, the dissociation rate for Mg2+ is believed to determine the physiological properties of parvalbumin and its ability to aid in relaxation. Previous work on the sheapshead assumes that there are differences in the Ca2+ and Mg2+ binding characteristics of the isoforms of parvalbumin. Although studies have shown differences in the Ca2+ dissociation constant (KD) for parvalbumin from different fish species, there is presently no data on how Mg2+ dissociation rates (the key predictor of the role of parvalbumin in relaxation according to Hou) might vary between species or isoforms of a given species. To address this issue, we plan to study the Ca2+ and Mg2+ binding characteristics of parvalbumin isoforms in two fish, sheepshead and rainbow trout. Here we report the isolation and purification of parvalbumin isoforms from sheepshead and rainbow trout by gel filtration and anion-exchange chromatography. |
|
Undergraduate Research Poster Session: Biochemistry
2:30 PM-4:30 PM, Monday, 11 September 2006 Moscone Center -- Hall D, Poster
Division of Chemical Education |