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Published on: March 17, 2010
Effect of cysteine modification on creatine kinase aggregation.
He-Chang Zou1, Zhi-Rong Lü, Ye-Jing Wang
1Department of Biological Science and Biotechnology, Tsinghua University, Beijing 100084, People's Republic of China.
Applied Biochemistry and Biotechnology
|June 13, 2008
Summary
Cysteine modification affects creatine kinase (CK) aggregation, which follows first-order kinetics. Acidic conditions and osmolytes like glycine and proline can block this aggregation, offering insights into protein stability.
Area of Science:
- Biochemistry
- Protein Chemistry
- Enzyme Kinetics
Background:
- Creatine kinase (CK) aggregation is a significant concern in protein stability.
- Understanding the factors modulating CK aggregation is crucial for biochemical research.
Purpose of the Study:
- To investigate the impact of cysteine modification on creatine kinase (CK) aggregation.
- To elucidate the kinetics and mechanisms underlying CK aggregation.
- To identify strategies for preventing CK aggregation.
Main Methods:
- Studied CK aggregation under varying pH conditions with Zn2+.
- Utilized 5,5'-dithiobis-2-nitrobenzoic acid (DTNB) for cysteine modification.
- Analyzed aggregation kinetics and transition free-energy changes (DeltaDeltaG(AG)).
- Assessed the effect of dithiothreitol (DTT) and osmolytes (glycine, proline) on aggregation.
Main Results:
- CK aggregation kinetics followed first-order kinetics and was suppressed in acidic conditions.
- Cysteine modification with DTNB induced dose-dependent aggregation, decreasing DeltaDeltaG(AG).
- DTT treatment reduced aggregates and reactivated inactive CK, while Zn2+ and DTNB caused complete inactivation.
- Glycine and proline blocked aggregation by increasing DeltaDeltaG(AG) and suppressing hydrophobic surfaces.
Conclusions:
- Cysteine modification significantly influences CK aggregation, impacting transitional free energy and hydrophobic surface properties.
- Acidic conditions, DTT, and specific osmolytes offer effective strategies to inhibit CK aggregation.
- The study provides a protocol to block CK aggregation, relevant for protein stabilization.
