黃啟清 助理教授

　

基本資料

 英文姓名：HWANG CHI-CHING

聯絡/住宅地址：高雄醫學大學生化學科

聯絡電話：(07)3121101轉2305

傳真號碼：07-3218309

E-MAIL：cchwang@cc.kmu.edu.tw

 

 

學經歷

 成功大學/化學系/學士

美國猶他大學/化學所/博士 (1995)

美國北德州大學醫學院/生化及分子生物系/博士後研究員(1995 ~ 1996)

美國奧克拉荷馬大學/生化系/博士後研究員(1996 ~ 1999/1)

美國奧克拉荷馬大學醫學院/生化及分子生物系/博士後研究員 (1999/2 ~ 1999/11)

台灣神隆公司/研發部/研究員 (2000/1 ~ 2001/7)

 

 

現職

 高雄醫學大學/醫學系生化學科/助理教授(2001/8 ~ 迄今)

  

專長

酵素機構、酵素動力學、蛋白質化學、同位素效應

 

研究方向

Research in this laboratory studies the mechanism of enzyme-catalyzed reaction, enzyme kinetics, and protein chemistry.

Currently the enzyme has been studied is 3alpha-hydroxysteroid dehydrogenase, an oxidoreductase, which belongs to the family of short-chain dehydrogenases/reductases (SDR).  One of the physiological functions of SDR enzymes is to regulate the cellular availability of a hormone receptor ligand by controlling the amount of active hormone.  Hence, it is a target for drug design, especially in breast and prostate cancer treatment.

Short-chain dehydrogenases/reductases (SDR) are either homodimers or tetramers, constitute a large protein family with highly diverse functions in pro- and eukaryotes.  Protein dimerization and oligomerization can confer several different structural and functional advantages to proteins, including the improved stability, the accessibility and specificity of active sites, and the increased complexity or the formation of pathogenic structures.  We are interesting in the interrelationship between subunit assembly, substrate specificity and enzyme function within SDR family to shed more light on the protein oligomerization and their function.

3a-hydroxysteroid dehydrogenase (3a-HSD, E.C. 1.1.1.50) from Comamonas testosteroni reversibly catalyses the oxidation of 3a-hydroxysteroids with nucleotide NAD+.  It is one of the enzymes involved in the initial stage of the steroid catabolic pathway and, therefore, plays a central role in steroid metabolism.  Structurally, the SDR enzymes have a Rossmann-fold consisting of bab-units forming a central six-stranded parallel b-sheet sandwiched between two arrays of a-helices.  Sequence alignment of SDR family typically exhibits residue identities only at the 15-30% level.  Only one residue is strictly conserved (Tyr 155 in 3a-HSD) with largely conserved residue of Lys159 and Ser114.  The 3a-HSD primary structure shows two sequence motifs which are common to the members of the SDR family.  These are the amino terminal Gly8-X-X-X-Gly12-X-Gly14 cofactor binding motif and the Tyr155-X-X-X-Lys159 motif which is located in the active site and forms with the conserved Ser114 a catalytic triad.

     Research will focus on the enzyme mechanism including the role of the functional groups involved in substrate binding, catalysis, structure-functional relationship, and protein oligomerization in the short-chain dehydrogenases/reductases.  Technique including steady-state rate measurements, spectroscopic studies, recombinant enzyme, site-directed mutagenesis, isotope effect studies, mass spectrometric analysis for noncovalent complex, protein purification and characterization, synthesis of substrate and analogs, and data analysis will be utilized for the studies.

 

執行之專題研究計畫

 1. 來探索3a-Hydroxysteroid Dehydrogenase之反應機構

   (NSC 90-2320-B-037-053)(主持人)

2. 3a-Hydroxysteroid Dehydrogenase催化反應之機構研究

   (NSC 91-2320-B-037-064)(主持人)

3. 3a-Hydroxysteroid Dehydrogenase催化反應之官能基團探討

   (NSC 92-2320-B-037-063)(主持人)

4. 短鏈脫氫酶/還原酶保留基團Ser114, Tyr155, 及 Lys159之機構角色探討

        (NSC 93-2320-B-037-043) (主持人)

 

5. 短鏈脫氫酵素/還原酵素之蛋白質寡聚合化作用探討

        (NSC 94-2320-B-037-046)(主持人)

 

6. 3α-羥基類固醇脫氫酶/還原酶之寡聚合作用及其穩定性探討

        (NSC 95-2320-B-037-047)(主持人)

 

研究成果

 1.       Hwang, C.-C., Chang, Y.-H., Hsu, C.-N., Hsu, H.-H., Li, C.-W., & Pon, H.-I. (2005)”Mechanistic Roles of Ser114, Tyr155 and Lys159 in 3a-    Hydroxysteroid Dehydrogenase/Carbonyl Reductase from Comamonas testosterone” J. Biol. Chem, 285, 3522-3528.

2.       Gulati, U., Hwang, C.-C., Venkatramani, L., Gulati, S., Stray, S. J., Lee, J. T., Laver, W. G., Bochkarev, A., Zlotnick, A., & Air, G. M. (2002) "Antiboty Epitopes on the Neuraminidase of a Recent H3N2 Influenza Virus (A/Memphis/31/98)" J. Virol. 76, 12274-12280.

3.       Liu, D., Hwang, C.-C., & Cook, P. F. (2002) " Alternative Substrates for Malic Enzyme: Oxidative Decarboxylation of L-Aspartate" Biochemistry 41, 12200-12203.

4.       Stanley, T. M., Johnson, W. H., Jr., Burks, E. A., Whitman, C. P., Hwang, C.-C., & Cook, P. F. (2000) " Expression and Stereochemical and Isotope Effect Studies of Active 4-Oxalocrotonate Decarboxylase" Biochemistry 39, 718-726.

5.       Karsten, W. E., Chooback, L., Liu, D., Hwang, C.-C., Lynch, C., & Cook, P. F. (1999) "Mapping the Active Site Topography of the NAD-Malic Enzyme via Alanine-Scanning Site-Directed Mutagenesis" Biochemistry 38, 10527-10532.

6.       Ehrlich, J. I., Hwang, C.-C., Cook, P. F., & Blanchard, J. S. (1999) "Evidence for a Stepwise Mechanism of OMP Decarboxylase" J. Am. Chem. Soc. 121, 6966-6967.

7.      Karsten, W. E., Hwang, C.-C., & Cook, P. F. (1999) "a-Secondary Tritium Kinetic Isotope Effects Indicate Hydrogen Tunneling and Coupled Motion in the Oxidation of L-Malate by NAD-Malic Enzyme"  Biochemistry 38, 4398-4402.

8.      Hwang, C.-C., & Cook, P. F. (1998) "Multiple Isotope Effects as a Probe of Proton and Hydride Transfer in the 6-Phosphogluconate Dehydrogenase Reaction" Biochemistry 37, 15698-15702.

9.      Hwang, C.-C., Berdis, A., Karsten, W. E., Cleland, W. W., & Cook, P.F. (1998) 幈"Oxidative Decarboxylation of 6-Phosphogluconate Dehydrogenase Proceeds by a Stepwise Mechanism with NADP and APADP as Oxidants" Biochemistry 37, 12596-12602.

10.   Cook, P. F., Tai, C. -H., Hwang, C.-C., Woehl, E. U., Dunn, M. F., & Schnackerz, K. D. (1996) 廍"Substitution of Pyridoxal 5'-Phosphate in the O-Acetylserine Sulhydrylase from Salmonella typhimurium by Cofactor Analogs Provides a Test of the Mechanism Proposed for Formation of the a-Aminoacrylate Intermediate" J. Biol. Chem. 271, 25842-25849.

11.   Hwang, C.-C., Woehl, E. U., Minter, D. E., Dunn, M. F., & Cook, P. F. (1996) "Kinetic Isotope Effects as a Probe of the b-Elimination Reaction Catalyzed by O-Acetylserine Sulfhydrylase" Biochemistry 35, 6358-6365.

12.   Hwang, C. -C. and Grissom, C. B. (1994) "Unusually Large Isotope Effects in Soybean Lipoxygenase Are Not Caused by a Magnetic Isotope Effect" J. Am. Chem. Soc. 116, 795-796.

13.   Yeh, M. Y., Tien, H. J., Tung, C. H., & Hwang, C. -C. (1988) "A Convenient Method for the Preparation of Nitriles from Aldehydes and Aldoximes.” J. Chinese Chem. Soc. 35, 459-462.

　

Book Chapter

Hwang, C. -C. and Grissom, C. B. (1996) "Large Deuterium Kinetic Isotope Effects in Soybean Lipoxygenase” in Lipoxygenase and Lipoxygenase pathway enzyme, Chapter 7, Piazza, G. J., Ed., AOCS Press, Champaign, Illinois, pp116-137.

 

Poster Abstracts

1. Yi-Hsun Chang, Tzu-Jung Huang and Chi-Ching Hwang “The mechanism of proton relay in the active site of the 3a-Hydroxysteroid    Dehydrogenase/Carbonyl Reductase from Comamonas testosteroni” Trends in Enzymology, Como city, Italy, June 7-10, 2006

2. Tzu-Jung Huang, Chao-Nan Hsun, Yi-Hsun Chang, Chi-Ching Hwang “The electronic interaction of Asp249 and Arg167 contributes in the oligomerization of 3a-Hydroxysteroid Dehydrogenase/Carbonyl Reductase from Comamonas testosteroni” The 20th joint annual conference of biomedical sciences, Taipei, Taiwan, March, 2006

3. Hwang, C.-C., Chang, Y.-H., Hsu, C.-N., Hsu, H.-H., Li, C.-W., & Pon, H.-I.  “Mechanistic Roles of Ser114, Tyr155 and Lys159 in 3a-Hydroxysteroid Dehydrogenase/Carbonyl Reductase from Comamonas testosterone” The 20th joint annual conference of biomedical sciences, Taipei, Taiwan, March, 2005.

4. Chang, Y.-H., and Hwang, C.-C. "The Catalytic Role of Conserved Y155 in 3a-Hydroxysteroid Dehydrogenase-catalyzed Reaction" The 19th joint annual conference of biomedical sciences, Taipei, Taiwan, April, 2004.

5. Hwang, C.-C., Hsu, H.-H., and Lee, J.-W. "Probing the Functional Roles of S114 and K159 on the 3a-Hydroxysteroid Dehydrogenase-catalyzed Reaction" The 19th joint annual conference of biomedical sciences, Taipei, Taiwan, April, 2004.

6. Hwang, C.-C., Jenn, T., Gani, D., & Cook, P. F. "Substrate Analogs as Structural Probes of the External Shiff Base of O-Acetylserine Sulfhydrylase: An Implication for the Closed Conformation" ASBMB meeting, San Francisco, CA., August 1997.

7. Hwang, C.-C., Woehl, E. U., Minter, D. E., Dunn, M. F., & Cook, P. F. "Kinetic Isotope Effects as a Probe of the b-Elimination Reaction Catalyzed by O-Acetylserine Sulfhydrylase" Isotopes in Biology and Chemistry, Golden Research Conference. Ventura, CA. February 11-16, 1996.

8. Grissom, C. B., and Hwang, C.-C. "Solvent Enhancement of Large Deuterium Kinetic Isotope Effects in Soybean Lipoxygenase Gives D(Vmax/Km) > 100: Is This a Binding Isotope Effect?" Isotopes in Biology and Chemistry, Golden Research Conference. Ventura, CA. February 11-16, 1996.

9. Hwang, C. -C. and Grissom, C. B. "Soybean Lipoxygenase Kinetic Isotope Effects: Organic Solvent Dependence of Large Kinetic Isotope Effect" ACS-DBC/ASBMB meeting, Washington, D. C. August 21, 1994.

10. Hwang, C. -C. and Grissom, C. B. "Soybean Lipoxygenase Kinetic Isotope Effects: Organic Solvent Dependence of Large Isotope Effect Suggests Amplification” Enzymes, Coenzymes, Metabolic Pathways Golden conference. July, 1994.

11. Hwang, C. -C. and Grissom, C. B. "Magnetic Field Effect Studies of Lipoxygenase- Catalyzed Oxidation of Linoleic Acid" Biochemistry 31, 2194 (1992).