Partial Purification of Acetic Acid Esterase from Malted Barley
F.J. Humberstone 1, 2 and D.E. Briggs 1, 3, 4
1Birmingham Malting and Brewing Group, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT
2Current address: Unipath Ltd, Priory Business Park, Bedford, MK44 3UP, UK
3Current address: 66 Sandhills Lane, Barnt Green, nr. Birmingham, B45 8NX, UK
4Corresponding author: Email: d.e.briggs@bham.ac.uk
J. Inst. Brew. 108(4), 434-438, 2002 | VIEW ARTICLE
ABSTRACT
Partial purifications (84, 114 and 390 fold) of a soluble acetic acid esterase from barley malt that degrades diacetin have been achieved. Enzyme recoveries were 20%, 20% and 25% in three consecutive runs. Initial problems of high viscosity and colour in the extract were overcome with the use of batch-elution anion exchange chromatography. This was followed by gradient elution anion exchange chromatography and gel filtration chromatography, which gave the greatest purification, but which gave erratic estimates of the molecular weight of the enzyme (40, 48 and 84 kDa). The apparent Km value of the acetyl esterase was tentatively estimated to be 25mM diacetin.
Key words:
Acetic acid esterase, barley malt, partial purification.
Publication no. G-2002-1223-001 ©2002 The Institute & Guild of Brewing