Enzymatic properties and regulation of ZPU1, the maize pullulanase-type starch debranching enzyme

被引:33
作者
Wu, CY [1 ]
Colleoni, C [1 ]
Myers, AM [1 ]
James, MG [1 ]
机构
[1] Iowa State Univ, Dept Biochem Biophys & Mol Biol, Ames, IA 50011 USA
关键词
starch; debranching enzyme; pullulanase; limit dextrinase; maize; Zea mays; endosperm; sugary; thioredoxin; enzyme kinetics;
D O I
10.1016/S0003-9861(02)00412-5
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
Starch debranching enzymes (DBE) are required for mobilization of carbohydrate reserves and for the normal structural organization of storage glucan polymers. Two isoforms, the pullulanase-type DBEs and the isoamylase-type DBEs, are both highly conserved in plants. To address DBE functions in starch assembly and breakdown, this study characterized the biochemical activity of ZPU1, a pullulanase-type DBE that is the product of the maize Zpu1 gene. Assays showed directly that recombinant ZPU1 (ZPU1r) expressed in Escherichia coli functions as a pullulanase-type enzyme, and H-1-NMR spectroscopy demonstrated that ZPU1r specifically hydrolyzes alpha(1 --> 6) branch linkages. Preferred substrates for ZPU1r hydrolytic activity were determined, as were pH, temperature, and thermal stability optima. Kinetic properties of ZPU1r with respect to two substrates, beta-limit dextrin and pullulan, were determined. ZPU1 activity was increased by incubation with thioredoxin h, and native activity was decreased in mutants that accumulate soluble sugars, suggesting potential regulatory mechanisms. (C) 2002 Elsevier Science (USA). All rights reserved.
引用
收藏
页码:21 / 32
页数:12
相关论文
共 51 条
[1]  
Ausubel FA, 1995, CURRENT PROTOCOLS MO
[2]   From glycogen to amylopectin: A model for the biogenesis of the plant starch granule [J].
Ball, S ;
Guan, HP ;
James, M ;
Myers, A ;
Keeling, P ;
Mouille, G ;
Buleon, A ;
Colonna, P ;
Preiss, J .
CELL, 1996, 86 (03) :349-352
[3]   Activation of the potato tuber ADP-glucose pyrophosphorylase by thioredoxin [J].
Ballicora, MA ;
Frueauf, JB ;
Fu, YB ;
Schürmann, P ;
Preiss, J .
JOURNAL OF BIOLOGICAL CHEMISTRY, 2000, 275 (02) :1315-1320
[4]   Purification and molecular genetic characterization of ZPU1, a pullulanase-type starch-debranching enzyme from maize [J].
Beatty, MK ;
Rahman, A ;
Cao, HP ;
Woodman, W ;
Lee, M ;
Myers, AM ;
James, MG .
PLANT PHYSIOLOGY, 1999, 119 (01) :255-266
[5]  
BEAVIS W, 1995, MAIZE GENET COOP NEW, V69, P182
[6]  
BRADFORD MM, 1976, ANAL BIOCHEM, V72, P248, DOI 10.1016/0003-2697(76)90527-3
[7]   Starch granule initiation and growth are altered in barley mutants that lack isoamylase activity [J].
Burton, RA ;
Jenner, H ;
Carrangis, L ;
Fahy, B ;
Fincher, GB ;
Hylton, C ;
Laurie, DA ;
Parker, M ;
Waite, D ;
van Wegen, S ;
Verhoeven, T ;
Denyer, K .
PLANT JOURNAL, 2002, 31 (01) :97-112
[8]   Overexpression of thioredoxin h leads to enhanced activity of starch debranching enzyme (pullulanase) in barley grain [J].
Cho, MJ ;
Wong, LH ;
Marx, C ;
Jiang, W ;
Lemaux, PG ;
Buchanan, BB .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 1999, 96 (25) :14641-14646
[9]  
Correns C, 1901, BIBLIOTHECA BOT, V53, P1
[10]  
Creech R.G., 1968, ADV AGRON, V20, P275, DOI [10.1016/S0065-2113, DOI 10.1016/S0065-2113, DOI 10.1016/S0065-2113(08)60859-7]