Linked Life Data

7873553

Source:http://linkedlifedata.com/resource/pubmed/id/7873553

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
8
pubmed:dateCreated
1995-4-4
pubmed:abstractText
A plasmid expression vector, pINSAT2, was constructed in order to express spermidine/spermine N1-acetyltransferase (SSAT) in Escherichia coli. Cells transfected with this vector produced large amounts of SSAT, amounting to up to 2% of the soluble protein when isopropyl beta-D-thiogalactopyranoside (IPTG) was added and 0.3% of the soluble protein in the absence of inducer. The growth rate of cells expressing SSAT was reduced, and all of the cellular spermidine was converted to N1-acetylspermidine, much of which was excreted. Putrescine and 1-methylspermidine, which is not a substrate for SSAT, could reverse the effects of SSAT expression on growth, but spermidine was only effective when the amount of SSAT expression was limited by omitting the IPTG inducer. The lack of stimulation of growth by spermidine correlated with its complete conversion to N1-acetylspermidine. These results show that N1-acetylspermine is not able to substitute for the unmodified polyamines in supporting growth and suggest that acetylation is a physiological response to convert excess polyamines to a physiologically inert form which is readily excreted. Cells expressing large amounts of SSAT were much more sensitive to the growth inhibitory action of the antitumor agent N1,N12-bis(ethyl)spermine, supporting the hypothesis that the ability of such bis(ethyl) polyamines to induce SSAT contributes to their antiproliferative actions. SSAT was readily purified to homogeneity from extracts of DH5 alpha cells containing pINSAT2. The purified enzyme had a similar specific activity and Km values for spermine and spermidine as the enzyme purified from human colon cancer cells, suggesting that posttranslational modifications specific to eukaryotes are not needed for enzymatic activity.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
28
pubmed:volume
34
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2701-9
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Effect of expression of human spermidine/spermine N1-acetyltransferase in Escherichia coli.
pubmed:affiliation
Department of Cellular and Molecular Physiology, Milton S. Hershey Medical Center, Pennsylvania State University College of Medicine, Hershey 17033.
pubmed:publicationType
Journal Article, In Vitro, 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