MetaCyc Pathway: starch degradation I
Inferred from experiment

Enzyme View:

Pathway diagram: starch degradation I

Note: a dashed line (without arrowheads) between two compound names is meant to imply that the two names are just different instantiations of the same compound -- i.e. one may be a specific name and the other a general name, or they may both represent the same compound in different stages of a polymerization-type pathway. This view shows enzymes only for those organisms listed below, in the list of taxa known to possess the pathway. If an enzyme name is shown in bold, there is experimental evidence for this enzymatic activity.

Synonyms: starch mobilization from cereal endosperm, starch degradation from cereal endosperm

Superclasses: Degradation/Utilization/AssimilationCarbohydrates DegradationPolysaccharides DegradationGlycans Degradation
Degradation/Utilization/AssimilationCarbohydrates DegradationPolysaccharides DegradationStarch Degradation
Degradation/Utilization/AssimilationPolymeric Compounds DegradationPolysaccharides DegradationGlycans Degradation
Degradation/Utilization/AssimilationPolymeric Compounds DegradationPolysaccharides DegradationStarch Degradation

Some taxa known to possess this pathway include : Hordeum vulgare, Oryza sativa, Zea mays

Expected Taxonomic Range: Poaceae

General Background

Plants accumulate and mobilize starch in both photosynthetic tissue (leaves) and non-photosynthetic storage tissues (such as tuber and seed endosperm). In leaves, starch is synthesized during the light period and is degraded during the dark period. In storage tissues, starch is degraded during tuber sprouting and seed germinating. Except for seed endosperm where starch degradation occurs in an acellular tissue, starch degradation generally occurs in the plastids (chloroplast of leaves and amyloplast of tubers) where starch accumulates. Isoforms of the starch degradation enzymes are also found and in many cases abundant in extra-plastidic subcellular locations in leaves and tubers. Their physiological functions are not well understood [Zeeman10].

About This Pathway

This pathway represents the starch degradation route present in the endosperm of cereal crops. Many details of the pathway as well as the relative importance of the four types of enzymes that contribute to this process, namely α-amylases, β-amylases, limit dextran debranching enzymes, and α-glucosidases, are still the subject of investigation and debate [Zeeman10, Stanley11].

Citations: [Kossmann00, Finnie11, Sun91, Rejzek11, Wu02]

Variants: starch degradation II, starch degradation III, starch degradation IV, starch degradation V

Unification Links: PlantCyc:PWY-842

Created 16-Feb-2011 by Zhang P, TAIR, PMN
Revised 07-Mar-2013 by Dreher KA, PMN
Revised 26-Sep-2014 by Caspi R, SRI International


Finnie11: Finnie C, Andersen B, Shahpiri A, Svensson B (2011). "Proteomes of the barley aleurone layer: A model system for plant signalling and protein secretion." Proteomics 11(9);1595-605. PMID: 21433287

Kossmann00: Kossmann J, Lloyd J (2000). "Understanding and influencing starch biochemistry." Crit Rev Biochem Mol Biol 2000;35(3);141-96. PMID: 10907795

Mu01: Mu HH, Yu Y, Wasserman BP, Carman GM (2001). "Purification and characterization of the maize amyloplast stromal 112-kDa starch phosphorylase." Arch Biochem Biophys 388(1);155-64. PMID: 11361132

Rejzek11: Rejzek M, Stevenson CE, Southard AM, Stanley D, Denyer K, Smith AM, Naldrett MJ, Lawson DM, Field RA (2011). "Chemical genetics and cereal starch metabolism: structural basis of the non-covalent and covalent inhibition of barley β-amylase." Mol Biosyst 7(3);718-30. PMID: 21085740

Sogaard90: Sogaard M, Svensson B (1990). "Expression of cDNAs encoding barley alpha-amylase 1 and 2 in yeast and characterization of the secreted proteins." Gene 1990;94(2);173-9. PMID: 2258050

Stanley11: Stanley D, Rejzek M, Naested H, Smedley M, Otero S, Fahy B, Thorpe F, Nash RJ, Harwood W, Svensson B, Denyer K, Field RA, Smith AM (2011). "The role of alpha-glucosidase in germinating barley grains." Plant Physiol 155(2);932-43. PMID: 21098673

Sun91: Sun ZT, Henson CA (1991). "A quantitative assessment of the importance of barley seed alpha-amylase, beta-amylase, debranching enzyme, and alpha-glucosidase in starch degradation." Arch Biochem Biophys 284(2);298-305. PMID: 1824915

Wu02: Wu C, Colleoni C, Myers AM, James MG (2002). "Enzymatic properties and regulation of ZPU1, the maize pullulanase-type starch debranching enzyme." Arch Biochem Biophys 406(1);21-32. PMID: 12234486

Zeeman10: Zeeman SC, Kossmann J, Smith AM (2010). "Starch: its metabolism, evolution, and biotechnological modification in plants." Annu Rev Plant Biol 61;209-34. PMID: 20192737

Other References Related to Enzymes, Genes, Subpathways, and Substrates of this Pathway

Ball03: Ball SG, Morell MK (2003). "From bacterial glycogen to starch: understanding the biogenesis of the plant starch granule." Annu Rev Plant Biol 54;207-33. PMID: 14502990

Ball11: Ball S, Colleoni C, Cenci U, Raj JN, Tirtiaux C (2011). "The evolution of glycogen and starch metabolism in eukaryotes gives molecular clues to understand the establishment of plastid endosymbiosis." J Exp Bot 62(6);1775-801. PMID: 21220783

Buleon98: Buleon A, Colonna P, Planchot V, Ball S (1998). "Starch granules: structure and biosynthesis." Int J Biol Macromol 23(2);85-112. PMID: 9730163

Frandsen00: Frandsen TP, Lok F, Mirgorodskaya E, Roepstorff P, Svensson B (2000). "Purification, enzymatic characterization, and nucleotide sequence of a high-isoelectric-point alpha-glucosidase from barley malt." Plant Physiol 123(1);275-86. PMID: 10806244

Latendresse13: Latendresse M. (2013). "Computing Gibbs Free Energy of Compounds and Reactions in MetaCyc."

Naested06: Naested H, Kramhoft B, Lok F, Bojsen K, Yu S, Svensson B (2006). "Production of enzymatically active recombinant full-length barley high pI alpha-glucosidase of glycoside family 31 by high cell-density fermentation of Pichia pastoris and affinity purification." Protein Expr Purif 46(1);56-63. PMID: 16343940

Stryer88: Stryer L "Biochemistry." WH Freeman and Co., 3rd edition, New York, 1988.

Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
Page generated by SRI International Pathway Tools version 19.5 on Sat Nov 28, 2015, BIOCYC11A.