Linked Life Data

7972516

Source:http://linkedlifedata.com/resource/pubmed/id/7972516

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1994-12-12
pubmed:abstractText
Two alpha-L-rhamnohydrolases with different substrate specificities were isolated from a commercial preparation produced by Aspergillus aculeatus. The first rhamnohydrolase was active toward p-nitrophenyl-alpha-L- rhamnopyranoside, naringin, and hesperidin and was termed p-nitrophenyl-alpha-L-rhamnopyranohydrolase (pnp-rhamnohydrolase). From the data collected, the enzyme seemed specific for the alpha-1,2- or alpha-1,6-linkage to beta-D-glucose. The pnp-rhamnohydrolase had a molecular mass of 87 kD (sodium dodecyl sulfate-polyacrylamide gel electrophoresis), a pH optimum of 5.5 to 6, a temperature optimum of 60 degrees C, and a specific activity toward pnp-alpha-L-rhamnopyranoside (pnp-Rha) of 13 units mg-1 protein. The second rhamnohydrolase, on the contrary, was active toward rhamnogalacturonan (RG) fragments, releasing Rha, and was therefore termed RG-rhamnohydrolase. The RG-rhamnohydrolase had a molecular mass of 84 kD, a pH optimum of 4, a temperature optimum of 60 degrees C, and a specific activity toward RG oligomers of 60 units mg-1 protein. The RG-rhamnohydrolase liberated Rha from the nonreducing end of the RG chain and appeared specific for the alpha-1,4-linkage to alpha-D-galacturonic acid. The enzyme was hindered when this terminal Rha residue was substituted at the 4-position by a beta-D-galactose. The results so far obtained did not indicate particular preference of the enzyme for low or high molecular mass RG fragments. From the results it can be concluded that a new enzyme, an RG alpha-L-rhamnopyranohydrolase, has been isolated with high specificity toward RG regions of pectin.
pubmed:commentsCorrections
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0032-0889
pubmed:author
pubmed:issnType
Print
pubmed:volume
106
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
241-50
pubmed:dateRevised
2009-11-18
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
Rhamnogalacturonan alpha-L-rhamnopyranohydrolase. A novel enzyme specific for the terminal nonreducing rhamnosyl unit in rhamnogalacturonan regions of pectin.
pubmed:affiliation
Wageningen Agricultural University, Department of Food Chemistry, The Netherlands.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't