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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
391
pubmed:dateCreated
2003-9-23
pubmed:abstractText
Proteins of the serpin superfamily (approximately 43 kDa) from mature cereal grains are in vitro suicide-substrate inhibitors of specific mammalian serine proteinases of the chymotrypsin family. However, unlike the 'standard-mechanism' serine proteinase inhibitors (<25 kDa), the biological functions of plant serpins are unknown. Expression studies of genes encoding members of three subfamilies of serpins (BSZx, BSZ4 and BSZ7) in developing grain and vegetative tissues of barley (Hordeum vulgare L.) showed that transcripts encoding BSZx, which inhibits distinct proteinases at overlapping reactive centres in vitro, were ubiquitous at low levels, but the protein could not be detected. EST analysis showed that expression of genes for serpins with BSZx-type reactive centres in vegetative tissues is widespread in the plant kingdom, suggesting a common regulatory function. For BSZ4 and BSZ7, expression at the protein level was highest in the maturing grain (> or d post-anthesis), where these serpins were localized by immunomicroscopy to the central and peripheral starchy endosperm, subaleurone, and (at lower levels) to the aleurone. Serpins were also localized to the meristem and vascular tissues of roots, and to the phloem of coleoptiles and leaves. The identification of BSZ4 in vegetative tissues by western blotting was confirmed for the roots by purification and amino acid sequencing, and for the leaves by in vitro reactive-centre loop cleavage studies. Plant serpins are likely to use their irreversible inhibitory mechanism in the inhibition of exogenous proteinases capable of breaking down seed storage proteins, and in the defence of specific cell types in vegetative tissues.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0022-0957
pubmed:author
pubmed:issnType
Print
pubmed:volume
54
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2251-63
pubmed:dateRevised
2004-11-17
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
Differential gene expression for suicide-substrate serine proteinase inhibitors (serpins) in vegetative and grain tissues of barley.
pubmed:affiliation
Biochemistry and Nutrition, BioCentrum, Building 224, Technical University of Denmark, DK-2800 Lyngby, Denmark. troberts@els.mq.edu.au
pubmed:publicationType
Journal Article