Send to

Choose Destination
J Biochem. 1989 Apr;105(4):573-6.

Identification of glutamic acid 186 affinity-labeled by 2,3-epoxypropyl alpha-D-glucopyranoside in soybean beta-amylase.

Author information

Laboratory of Biophysical Chemistry, College of Agriculture, University of Osaka Prefecture.


Soybean beta-amylase was modified with 2,3-epoxypropyl alpha-D-[U-14C]glucopyranoside ([14C]alpha-EPG), a radioactive affinity-labeling reagent for beta-amylase, until it lost 95% of its enzyme activity. After S-carboxymethylation at pH 8.0 of SH groups, the modified enzyme was digested at pH 7.0 with Achromobacter protease I and the digest was fractionated by reverse-phase HPLC. A radioactive peptide was finally isolated and its amino acid sequence was determined to be 181Leu-Gly-Pro-Ala-Gly-Glu186. Radioactivity derived from [14C]-alpha-EPG was found exclusively at Glu-186, the gamma-carboxyl group of which is esterified with the affinity label. It was concluded that the carboxylate of Glu-186 is a functional group at the catalytic site of soybean beta-amylase.

[Indexed for MEDLINE]
Free full text

Supplemental Content

Full text links

Icon for J-STAGE, Japan Science and Technology Information Aggregator, Electronic
Loading ...
Support Center