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Isozyme hybrids within the protruding third loop domain of the barley alpha-amylase (beta/alpha)8-barrel. Implication for BASI sensitivity and substrate affinity.
- Source :
-
FEBS letters [FEBS Lett] 1995 Apr 24; Vol. 363 (3), pp. 299-303. - Publication Year :
- 1995
-
Abstract
- Barley alpha-amylase isozymes AMY1 and AMY2 contain three structural domains: a catalytic (beta/alpha)8-barrel (domain A) with a protruding loop (domain B; residues 89-152) that binds Ca2+, and a small C-terminal domain. Different parts of domain B secure isozyme specific properties as identified for three AMY1-AMY2 hybrids, obtained by homeologous recombination in yeast, with crossing-over at residues 112, 116, and 144. The AMY1 regions Val90-Thr112 and Ala145-Leu161 thus confer high affinities for the substrates alpha-D-maltoheptaoside and amylose, respectively. Leu117-Phe144, and to a lesser degree Ala145-Leu161, are critical for the stability at low pH characteristic of AMY1 and for the sensitivity to barley alpha-amylase/subtilisin inhibitor specific to AMY2.
Details
- Language :
- English
- ISSN :
- 0014-5793
- Volume :
- 363
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- FEBS letters
- Publication Type :
- Academic Journal
- Accession number :
- 7737421
- Full Text :
- https://doi.org/10.1016/0014-5793(95)00291-g