Application of Bronsted-type LFER in the study of the phospholipase C mechanism

被引:17
作者
Mihai, C
Kravchuk, AV
Tsai, MD
Bruzik, KS [1 ]
机构
[1] Univ Illinois, Dept Med Chem & Pharmacognosy, Chicago, IL 60612 USA
[2] Ohio State Univ, Dept Chem, Columbus, OH 43210 USA
关键词
D O I
10.1021/ja029362s
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
Phosphaticlylinositol-specific phospholipase C cleaves the phosphodiester bond of phosphatidylinositol to form inositol 1,2-cyclic phosphate and diacylglycerol. This enzyme also accepts a variety of alkyl and aryl inositol phosphates as substrates, making it a suitable model enzyme for studying mechanism of phosphoryl transfer by probing the linear free-energy relationship (LFER). In this work, we conducted a study of Bronsted-type relationship (log k = beta(Ig) pK(a) + C) to compare mechanisms of enzymatic and nonenzymatic reactions, confirm the earlier proposed mechanism, and assess further the role of hydrophobicity in the leaving group as a general acid-enabling factor. The observation of the high negative Bronsted coefficients for both nonenzymatic (beta(Ig) = -0.65 to -0.73) and enzymatic cleavage of aryl and nonhydrophobic alkyl inositol phosphates (beta(Ig) = -0.58) indicates that these reactions involve only weak general acid catalysis. In contrast, the enzymatic cleavage of hydrophobic alkyl inositol phosphates showed low negative Bronsted coefficient (beta(Ig) = -0.12), indicating a small amount of the negative charge on the leaving group and efficient general acid catalysis. Overall, our results firmly support the previously postulated mechanism where hydrophobic interactions between the enzyme and remote parts of the leaving group induce an unprecedented negative-charge stabilization on the leaving group in the transition state.
引用
收藏
页码:3236 / 3242
页数:7
相关论文
共 32 条
[1]  
AQUIST J, 1999, CHEM BIOL, V6, pR71
[2]  
Bruzik K S, 1994, Bioorg Med Chem, V2, P49, DOI 10.1016/S0968-0896(00)82002-7
[3]   PHOSPHOLIPIDS CHIRAL AT PHOSPHORUS - STEREOCHEMICAL MECHANISM FOR THE FORMATION OF INOSITOL 1-PHOSPHATE CATALYZED BY PHOSPHATIDYLINOSITOL-SPECIFIC PHOSPHOLIPASE-C [J].
BRUZIK, KS ;
MOROCHO, AM ;
JHON, DY ;
RHEE, SG ;
TSAI, MD .
BIOCHEMISTRY, 1992, 31 (22) :5183-5193
[4]   Synthesis of inositol phosphodiesters by phospholipase C-catalyzed transesterification [J].
Bruzik, KS ;
Guan, ZW ;
Riddle, S ;
Tsai, MD .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1996, 118 (33) :7679-7688
[5]   EXPERIMENTAL CHARGE MEASUREMENT AT LEAVING OXYGEN IN THE BOVINE RIBONUCLEASE A CATALYZED CYCLIZATION OF URIDINE 3'-PHOSPHATE ARYL ESTERS [J].
DAVIS, AM ;
REGAN, AC ;
WILLIAMS, A .
BIOCHEMISTRY, 1988, 27 (25) :9042-9047
[6]   CHARGE DESCRIPTION OF BASE-CATALYZED ALCOHOLYSIS OF ARYL PHOSPHODIESTERS - A RIBONUCLEASE MODEL [J].
DAVIS, AM ;
HALL, AD ;
WILLIAMS, A .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1988, 110 (15) :5105-5108
[7]   Probing the roles of active site residues in phosphatidylinositol-specific phospholipase C from Bacillus cereus by site-directed mutagenesis [J].
Gassler, CS ;
Ryan, M ;
Liu, T ;
Griffith, OH ;
Heinz, DW .
BIOCHEMISTRY, 1997, 36 (42) :12802-12813
[8]   LEAVING GROUP DEPENDENCE IN THE PHOSPHORYLATION OF ESCHERICHIA-COLI ALKALINE-PHOSPHATASE BY MONOPHOSPHATE ESTERS [J].
HALL, AD ;
WILLIAMS, A .
BIOCHEMISTRY, 1986, 25 (17) :4784-4790
[9]   RIBONUCLEASE REVISITED - CATALYSIS VIA THE CLASSICAL GENERAL ACID-BASE MECHANISM OR A TRIESTER-LIKE MECHANISM [J].
HERSCHLAG, D .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1994, 116 (26) :11631-11635
[10]   PHOSPHORYL TRANSFER TO ANIONIC OXYGEN NUCLEOPHILES - NATURE OF THE TRANSITION-STATE AND ELECTROSTATIC REPULSION [J].
HERSCHLAG, D ;
JENCKS, WP .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1989, 111 (19) :7587-7596