|
type |
Journal Article |
authors |
De-Eknamkul, W.; Ellis, B.E. |
title |
Purification and characterization of prephenate aminotransferase from Anchusa officinalis cell cultures |
journal |
Arch Biochem Biophys |
Activity |
2.6.1.78 |
sel |
selected |
ui |
3196038 |
year |
(1988) |
volume |
267 |
number |
1 |
pages |
87-94 |
| |
abstract |
Prephenate aminotransferase (PAT) from rosmarinic acid-producing cell cultures of Anchusa officinalis has been purified to apparent electrophoretic homogeneity using a combination of high-performance anion-exchange, chromatofocusing, and gel filtration chromatography. The purified enzyme has a native molecular weight of 220,000 and subunit molecular weights of 44,000 and 57,000, indicating a possible alpha 2 beta 2 subunit structure. The purified PAT displays high affinity for prephenate (Km = 80 microM) but could also utilize other aromatic alpha-keto acids at less than 20% the rate with prephenate. L-Aspartate (Km = 80 microM) is about three times as effective as L-glutamate as amino-donor substrate. Anchusa PAT is not subject to feedback inhibition from L-phenylalanine or tyrosine, but its activity is affected by a rosmarinic acid metabolite, 3,4-dihydroxyphenyllactic acid. |
last changed |
2009/05/19 17:48 |
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