Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
44
pubmed:dateCreated
1994-11-29
pubmed:databankReference
pubmed:abstractText
delta 6 Hexadecenoic acid (16:1 delta 6) composes more than 80% of the seed oil of Thunbergia alata. Studies were conducted to determine the biosynthetic origin of the double bond of this unusual fatty acid. Assays of fractions of developing T. alata seed endosperm with [1-14C]palmitoyl (16:0)-acyl carrier protein (ACP) revealed the presence of a soluble delta 6 desaturase activity. This activity was greatest when 16:0-ACP was provided as a substrate, whereas no desaturation of the coenzyme A ester of this fatty acid was detected. In addition, delta 6 16:0-ACP desaturase activity in T. alata endosperm extracts was dependent on the presence of ferredoxin and molecular oxygen and was stimulated by catalase. To further characterize this enzyme, a cDNA encoding a diverged acyl-ACP desaturase was isolated from a T. alata endosperm cDNA library using polymerase chain reaction with degenerate oligonucleotides corresponding to conserved amino acid sequences in delta 9 stearoyl (18:0)- and delta 4 16:0-ACP desaturases. The primary structure of the mature peptide encoded by this cDNA shares 66% identity with the mature castor delta 9 18:0-ACP desaturase and 57% identity with the mature coriander delta 4 16:0-ACP desaturase. Extracts of Escherichia coli that express the T. alata cDNA catalyzed the delta 6 desaturation of 16:0-ACP. These results demonstrate that 16:1 delta 6 in T. alata endosperm is formed by the activity of a soluble delta 6 16:0-ACP desaturase that is structurally related to the delta 9 18:0- and delta 4 16:0-ACP desaturases. Implications of this work to an understanding of active site structures of acyl-ACP desaturases are discussed.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
http://linkedlifedata.com/resource/pubmed/chemical/Catalase, http://linkedlifedata.com/resource/pubmed/chemical/DNA, Complementary, http://linkedlifedata.com/resource/pubmed/chemical/Fatty Acid Desaturases, http://linkedlifedata.com/resource/pubmed/chemical/Fatty Acids, Monounsaturated, http://linkedlifedata.com/resource/pubmed/chemical/Ferredoxins, http://linkedlifedata.com/resource/pubmed/chemical/Hydrogen Peroxide, http://linkedlifedata.com/resource/pubmed/chemical/Linoleoyl-CoA Desaturase, http://linkedlifedata.com/resource/pubmed/chemical/Nitrogen, http://linkedlifedata.com/resource/pubmed/chemical/Oils, http://linkedlifedata.com/resource/pubmed/chemical/Palmitates, http://linkedlifedata.com/resource/pubmed/chemical/Palmitic Acids, http://linkedlifedata.com/resource/pubmed/chemical/Potassium Cyanide
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
4
pubmed:volume
269
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
27519-26
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed-meshheading:7961667-Amino Acid Sequence, pubmed-meshheading:7961667-Base Sequence, pubmed-meshheading:7961667-Catalase, pubmed-meshheading:7961667-Cloning, Molecular, pubmed-meshheading:7961667-DNA, Complementary, pubmed-meshheading:7961667-Fatty Acid Desaturases, pubmed-meshheading:7961667-Fatty Acids, Monounsaturated, pubmed-meshheading:7961667-Ferredoxins, pubmed-meshheading:7961667-Hydrogen Peroxide, pubmed-meshheading:7961667-Linoleoyl-CoA Desaturase, pubmed-meshheading:7961667-Molecular Sequence Data, pubmed-meshheading:7961667-Nitrogen, pubmed-meshheading:7961667-Oils, pubmed-meshheading:7961667-Palmitates, pubmed-meshheading:7961667-Palmitic Acids, pubmed-meshheading:7961667-Plants, pubmed-meshheading:7961667-Potassium Cyanide, pubmed-meshheading:7961667-Seeds, pubmed-meshheading:7961667-Sequence Alignment, pubmed-meshheading:7961667-Sequence Homology, Amino Acid, pubmed-meshheading:7961667-Solubility, pubmed-meshheading:7961667-Substrate Specificity
pubmed:year
1994
pubmed:articleTitle
delta 6 Hexadecenoic acid is synthesized by the activity of a soluble delta 6 palmitoyl-acyl carrier protein desaturase in Thunbergia alata endosperm.
pubmed:affiliation
Department of Botany and Plant Pathology, Michigan State University, East Lansing 48824.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't