UniProt:D0TZF0 ISA1

chain
  • transit peptide:1-54
  • chain:55-803
checksum 9DC80176A72292E0
comment
  • FUNCTION Starch-debranching enzyme involved in amylopectin biosynthesis in endosperm. Functions by removing excess branches or improper branches that interfere with the formation of double helices of the cluster chains of amylopectin and crystallization of starch (PubMed:10517831, PubMed:15618430, PubMed:16953433, PubMed:21436381). Works as ISA1 homooligomer or together with ISA2 as heterooligomer. The heterooligomer ISA1 and ISA2 possesses higher affinity than the ISA1 homooligomer for various branched polyglucans in vitro, but no marked differences exist in chain preferences for debranching of amylopectin and phytoglycogen between these forms (PubMed:16953433, PubMed:21436381).CATALYTIC ACTIVITY Hydrolysis of (1->6)-alpha-D-glucosidic branch linkages in glycogen, amylopectin and their beta-limit dextrins.ACTIVITY REGULATION Inhibited by copper chloride, mercury chloride, ammonium molybdate and para-chloromercuribenzoate.BIOPHYSICOCHEMICAL PROPERTIES Optimum pH is 6.5 at 30 degrees Celsius.PATHWAY Glycan biosynthesis; starch biosynthesis.SUBUNIT Forms a homo-pentamer and a hetero-hexamer composed of five ISA1 and one ISA2 (PubMed:16953433). Interacts with FLO6/SIP4 (PubMed:24456533).SUBCELLULAR LOCATION Highly expressed in developing endosperm. Expressed at low levels in leaves.DISRUPTION PHENOTYPE Replacement of endosperm starch by a water-soluble highly and randomly branched polysaccharide structure called phytoglycogen.SIMILARITY Belongs to the glycosyl hydrolase 13 family.SEQUENCE CAUTION Sequencing errors.SEQUENCE CAUTION Truncated N-terminus.SEQUENCE CAUTION Truncated N-terminus.
created [InstanceEdit:1164949] Wu, Guanming, 2010-12-11
crossReference
databaseName UniProt
dbId 1162704
description
  • recommendedName: fullName evidence="12"Isoamylase 1, chloroplastic shortName evidence="10"OsISA1 ecNumber evidence="3"3.2.1.68 alternativeName: fullName evidence="10"Protein SUGARY-1
displayName UniProt:D0TZF0 ISA1
geneName
  • ISA1
  • Os08g0520900
  • LOC_Os08g40930
  • ISA
  • SU1
identifier D0TZF0
isSequenceChanged false
keyword
  • Carbohydrate metabolism
  • Chloroplast
  • Direct protein sequencing
  • Glycosidase
  • Hydrolase
  • Plastid
  • Reference proteome
  • Starch biosynthesis
  • Transit peptide
modified [InstanceEdit:9918301] Naithani, Sushma, 2024-08-14
name
  • ISA1
referenceDatabase [ReferenceDatabase:2] UniProt
schemaClass ReferenceGeneProduct
secondaryIdentifier
  • ISOA1_ORYSJ
  • O80403
  • Q0J4C6
  • Q84L53
sequenceLength 803
species [Species:1250427] Oryza sativa subsp. japonica
url http://purl.uniprot.org/uniprot/D0TZF0