Dr. Joseph Hajdu

Professor of Biochemistry, Department of Chemistry

Email:

Phone:

(818) 677-3377

Office:

Citrus Hall 3108   

RESEARCH INTERESTS

Hajdu's current interest focuses on elucidation of the mechanism of action of lipolytic enzymes with specific emphasis on phospholipase A2.

Ongoing efforts are directed at:

• Kinetic characterization of lipolysis by the pancreatic enzyme acting on phosphatidylcholine-surfactant mixed micelles 
• Design and synthesis of specific and potent phospholipase inhibitors 
• Development of new assay systems for the study of lipid hydrolyzing enzymes 
• Bioorganic model studies of catalytic interactions in nonprotic acyl transfer reactions.

A related project aims at the synthesis of antitumor-active ether phospholipid derivatives. Other studies involve structural and mechanistic elucidation of the chemistry of the metal complexes of streptonigrin, a naturally occurring antitumor antibiotic.

REPRESENTATIVE PUBLICATIONS

1. "Synthesis of phospholipids on a glyceric acid scaffold: design and preparation of phospholipase A2 specific substrates" Rosseto R.; Hajdu J.  Tetrahedron (2014) 70, 3155-3165.
2. "Peptidophospholipids: Synthesis, phospholipase A2 catalyzed hydrolysis, and application to development of phospholipid prodrugs" Rosseto R.; Hajdu J., Chemistry and Physics of Lipids (2014) 183, 110-116.
3. "Synthesis of mixed-chain phosphatidylcholines including coumarin fluorophores for FRET-based kinetic studies of phospholipase A2 enzymes” Wang M.; Pinnamaraju S.; Ranganathan R; Hajdu J., Chemistry and Physics of Lipids (2013) 172, 78-85. 
4. "Surface dilution kinetics using substrate analog enantiomers as diluents: Enzymatic lipolysis by bee venom phospholipase A2” Singh J.; Ranganathan R; Hajdu J., Analytical Biochemistry (2010) 407, 253-260. 
5. “Synthesis of oligo(ethylene glycol) substituted phosphatidylcholines: Secretory PLA2-targeted precursors of NSAID prodrugs” Rosseto R.; Hajdu J., Chemistry and Physics of Lipids, (2010) 163, 110-116. 
6. "Kinetics of Bacterial Phospholipase C Activity at Micellar Interfaces: Effect of the Substrate Aggregate Microstructure and a Model for the Kinetic Parameters" Singh, J.; Ranganathan, R; Hajdu, J., J. Phys. Chem. B. (2008) 112, 16741-16751. 
7. "Characterization of Mixed Micelles of 1-2-Diheptanoyl-sn-Glycero-3-Phosphocholine (DHPC) and Sodium Dodecyl Sulfate, and DHPC and Dodecyl Trimethylammonium Bromide," Ranganathan, R.; Vautier-Giongo, C.; Bakshi, M.; Bales, B. L.; Hajdu, J., Chem. Phys. Lipids (2005) 135, 93-104. 
8. "A Rapid and Efficient Method for Migration-Free Acylation of Lysophospholipids: Synthesis of Phasphatidylcholines with sn-2-Chain-Terminal Reporter Groups," Rosseto, R.; Hajdu, J., Tetrahedron Lett. (2005) 46, 2941-2944. 
9. "Characterization of Mixed Micelles of 1-2-Diheptanoyl-sn-Glycero-3-Phosphocholine (DHPC) and Sodium Dodecyl Sulfate, and DHPC and Dodecyl Trimethylammonium Bromide," Ranganathan, R.; Vautier-Giongo, C.; Bakshi, M.; Bales, B. L.; Hajdu, J., Chem. Phys. Lipids (2005) 135, 93-104. 
10. "Effects of Interactions on the Formation of Mixed Micelles of 1-2,Diheptanoyl-sn-Glycero-3-Phosphocholine with Sodium Dodecyl Sulfate and Dodecyl Trimethylammonium Bromide," Vautier-Giongo, C.; Bakshi, S.; Singh, J.; Ranganathan, R.; Hajdu, J.; Bales, B. L., J. Colloid Interface Sci. (2005) 282, 149-155. 
11. "A New Approach to the Synthesis of Lysophospholipids: Preparation of Lysophosphatidic Acid and Lysophosphatidylcholine From p-Nitrophenyl Glycerate," Rosseto, R.; Bibak, N.; Hajdu, J., Tetrahedron Lett. (2004) 45, 7371-7373. 
12. "A New Approach to the Synthesis of Lysophosphatidylcholines and Related Derivatives," Bibak, N.; Hajdu, J., Tetrahedron Lett. (2003) 44, 5875-5877.
13. "Recent Advances in Phospholipid Synthesis," Hajdu, J., Recent Res. Devel. Lipids Res. (1999) 3, 165-189. 
14. "A New Approach to the Stereospecific Synthesis of Phospholipids. The Use of L-Glyceric Acid for the Preparation of Diacylglycerols, Phosphatidylcholines and Related Derivatives," Roodsari, F. S., Wu, D., Pum, G. S. and Hajdu, J., J. Org. Chem. (1999) 64, 7727. 
15. "Stereospecific Synthesis of Functionalized Ether Phospholipids," Kazi, A. B.; Shidmand, S. and Hajdu, J., J. Org. Chem. (1999) 64, 9337. 
16. "The Structure of Streptonigrin Semiquinone in Solution," Soedjak, H. S.; Hajdu, J.; Raffetto, J. D.; Cano, R.; Bales, B. L.; Prasad, L. S. and Kispert, L. D. Biochim. Biophys. Acta (1997) 1335, 73. 
17. "Preparation and ESR Spectroscopic Characterization of the Zinc(II) and Cadmium(II) Complexes of Streptonigrin Semiquinone," Soedjak, H. S.; Cano, R.; Tran, L.; Bales, B. L. and Hajdu, J. Biochim. Biophys. Acta (1997) 1335, 305. 
18. "A New Synthetic Ether Aminophosphoglyceride Exhibits Partial Modulator Activity Towards the Glucocorticoid Receptor," Bodine, P.V.N., Hajdu, J. and Litwack, G.A., Biochem. Biophys. Res. Commun. (1994) 203, 408. 
19. "Structure-Function Relationships of Alkyl-Lysophospholipid Analogs in Selective Antitumor Activity," Vogler, W.R., Olson, A.C., Hajdu, J., Shoji, S., Raynor, R. and Kuo, J.F., Lipids (1993) 28, 511. 
20. "Synthesis of Phospholipid Headgroups via Nucleophilic Ring Opening of 1,3,2-Dioxaphospholanes" Kim, U.T. and Hajdu, J., J. Chem. Soc., Chem Commun. (1993) 70. 
21. "Synthesis of Amino Acid Substituted Ether Phospholipids via 2,2,2-Trichloro-t-Butyl Phosphodichloridite Coupling," Kazi, A. B. and Hajdu, J., Tetrahedron Lett. (1992) 33, 2291. 
22. "Anticancer Activity and Effect on Protein Kinase C(PKC) of Synthetic Phospholipid Analogs," Vogler, W.R., Olson, A.C., Shoji, M., Kuo, J.F. and Hajdu, J., Dev. Oncol. (1991) 67, 453. 
23. "Stereospecific Synthesis of Antitumor Active PAF Analogs," Bhatia, S.K. and Hajdu. J., Lipids (1991) 26, 1424. 
24. "Comparison of Selective Cytotoxicity of Alkyl-lysophospholipids," Vogler, W.R., Olson, A.C., Okamato, S., Shoji, M., Raynor, R.L., Kuo, J. F., Berdel, W. E., Eible, H., J. and Nomura, H., Lipids (1991) 26, 1418. 
25. "Stereospecific Synthesis of Ether Phospholipids. Preparation of 1-O-(3'-Carboxypropyl-Glycero-3-Phosphoserine from Glyceric Acid," Srivastava, R.P. and Hajdu, J., Tetrahedron Lett. (1991) 32, 6525. 
26. "Stereospecific Synthesis of Ether Phospholipids. Preparation of 1-Octadecyl-2-Alkylaminodeoxyglycerophosphocholines," Kim, U.T., Bhatia, S.K. and Hajdu, J., Tetrahedron Lett. (1991) 32, 6521. 
27. "Phospholipids Containing Nitrogen and Sulphur Linked Chains: Kinetics of Cholesterol Exchange Between Vesicles," Kan, C.C., Bittman, T. and Hajdu, J., Biochem. Biophy. Acta (1991) 1066, 95.

M. S. THESES

• Synthesis and Characterization of Functionalized Ether Phospholipids with Fluorescent Chain-terminal Reporter Groups (2011) Kaur, J. 
• Kinetic Studies of Bee-venom Phospholipase A2 Acting on Fluorescently Labeled Phosphatidylcholine Analogue (2011) Pinnamaraju, S. 
• Stereospecific Synthesis and Characterization of Phosphatidylcholines with Fluorescent Chain-Terminal Reporter Groups (2006) Wang, M. 
• Chemistry of Quinolinequinone-Cadmium Complexes (2004) Siddiq, A. 
• A New Stereospecific Synthesis of Lysophosphatidycholine Derivatives (2004) Shah, T. 
• Stereospecific Synthesis of Functionalized Phosphatidylcholines (1996) Wu, D. Chemiluminescence Immunoassay for Pregnenolone (1996) Curtin, W. D., Jr. 
• ESR Studies on Streptonigrin Semiquinone and Its Metal Complexes (1995) Cano, R. 
• Kinetic Studies of Phospholipase A2 Toward Mixed Micelles (1994) Qureshi, A. 
• Synthesis of Structurally Modified Phospholipids (1991) Kim, U. T. 
• Catalytic Mechanisms of Acyl Transfer Reactions in Dipolar Aprotic Media (1990) Hyun, C. M. 
• Electron Spin Resonance Investigation of 5,8-Quinoline Semiquinone (1989) Raffetto, J. D. 
• Stereospecific Synthesis of Phospholipids (1989) Roodsari, F. S. 
• Generation and Electron Spin Resonance Characterization of 5,8-Quinoline Semiquinone Radicals (1988) Soedjak, H. S.