PHOSPHORIBOSYL ANTHRANILATE ISOMERASE CATALYZES A REVERSIBLE AMADORI REACTION

被引:52
作者
HOMMEL, U [1 ]
EBERHARD, M [1 ]
KIRSCHNER, K [1 ]
机构
[1] UNIV BASEL, BIOCTR, BIOPHYS CHEM ABT, CH-4056 BASEL, SWITZERLAND
关键词
D O I
10.1021/bi00016a014
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Data from steady state and transient kinetics show that the functional phosphoribosyl anthranilate isomerase domain of the naturally bifunctional enzyme from Escherichia coli has properties similar to those of its artificially excised domain. The naturally monofunctional enzyme from Saccharomyces cerevisiae has significantly higher values of both (k) over right arrow(cat) and (k) over right arrow/K-M(PRA). The primary product of a single turnover of phosphoribosylanthranilate is fluorescent, but it slowly isomerizes to the nonfluorescent stable product. The latter is the competent substrate of indoleglycerol phosphate synthase, which catalyzes the subsequent step of tryptophan biosynthesis. The isomerization is characterized by a monoexponential decay independent of phosphoribosyl anthranilate isomerase. Due to a tentative assignment of the fluorescent, primary product and the nonfluorescent, stable product to an enol and a keto compound, respectively, tryptophan biosynthesis appears to be rate-limited by an uncatalyzed enol/keto tautomerization. A formal kinetic mechanism of the reaction catalyzed by phosphoribosyl anthranilate isomerase is proposed that is consistent with the combined enzymic and ligand binding properties of the three variants of phosphoribosyl anthranilate isomerase.
引用
收藏
页码:5429 / 5439
页数:11
相关论文
共 39 条
  • [1] A NEW SPECTROPHOTOMETRIC ASSAY FOR DOPACHROME TAUTOMERASE
    AROCA, P
    SOLANO, F
    GARCIABORRON, JC
    LOZANO, JA
    [J]. JOURNAL OF BIOCHEMICAL AND BIOPHYSICAL METHODS, 1990, 21 (01): : 35 - 46
  • [2] ISOLATION AND PROPERTIES OF OXALOACETATE KETO-ENOL-TAUTOMERASES FROM BOVINE HEART-MITOCHONDRIA
    BELIKOVA, YO
    BUROV, VI
    VINOGRADOV, AD
    [J]. BIOCHIMICA ET BIOPHYSICA ACTA, 1988, 936 (01) : 10 - 19
  • [3] Bernasconi C. F., 1976, RELAXATION KINETICS
  • [4] N-(5-PHOSPHORIBOSYL)ANTHRANILATE ISOMERASE-INDOLEGLYCEROL-PHOSPHATE SYNTHASE .1. SUBSTRATE-ANALOG BINDS TO 2 DIFFERENT BINDING-SITES ON THE BIFUNCTIONAL ENZYME FROM ESCHERICHIA-COLI
    BISSWANGER, H
    KIRSCHNER, K
    COHN, W
    HAGER, V
    HANSSON, E
    [J]. BIOCHEMISTRY, 1979, 18 (26) : 5946 - 5953
  • [5] BRAUS GH, 1988, J BIOL CHEM, V263, P7868
  • [6] N-(5-PHOSPHORIBOSYL)ANTHRANILATE ISOMERASE-INDOLEGLYCEROL-PHOSPHATE SYNTHASE .2. FAST-REACTION STUDIES SHOW THAT A FLUORESCENT SUBSTRATE-ANALOG BINDS INDEPENDENTLY TO 2 DIFFERENT SITES
    COHN, W
    KIRSCHNER, K
    PAUL, C
    [J]. BIOCHEMISTRY, 1979, 18 (26) : 5953 - 5959
  • [7] EVOLUTION OF A BIOSYNTHETIC-PATHWAY - THE TRYPTOPHAN PARADIGM
    CRAWFORD, IP
    [J]. ANNUAL REVIEW OF MICROBIOLOGY, 1989, 43 : 567 - 600
  • [8] CREIGHTON T E, 1970, Biochemical Journal, V120, P699
  • [9] CREIGHTON TE, 1968, J BIOL CHEM, V243, P5605
  • [10] CREIGHTON TE, 1970, METHODS ENZYMOLOGY A, V17, P365, DOI DOI 10.1021/ACS.BIOCHEM.8B00167