(glyoxyl groups are able only to fix protein to the support if mul-tipoint covalent attachment is established [18]), or due to stericproblems for the reaction between an area rich in Lys of the pro-tein and the support due to the presence of sugar chains, as thisenzyme is glycosylated [32]. Although the three supports wereable to immobilize the enzyme, the expressed activities were verylow, especially when the MANAE support was used (Table 1). Thiscould be due to enzyme desorption during washings if the enzymeimmobilization was quite weak. However, the activity of the sus-pension before washing was as low as the activity recovered afterwashings, suggesting that a real inactivation of the enzyme hadoccurred.The glutaraldehyde-agarose derivative was the support thatgives the highest immobilization yields and expressed activityamong the three assayed ones (Table 1). Based on these observa-tions, the glutaraldehyde immobilized derivative has been used forall further studies.