Protease immobilization onto copoly(ethylene/acrylic acid) fiber

Emi, Shingo; Murase, Yasuhiro; Hayashi, Toshio; Nakajima, Akira

doi:10.1002/app.1990.070411121

Cited by 27 publications

(23 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Improved thermal stability of enzymes immobilized on solid carriers has been observed by many researchers. Such improvement has been explained as the reduced mobility of the enzyme after immobilization, 7,8,40 in support of our conclusion.…”

Section: Thermal Cyclingsupporting

confidence: 80%

See 1 more Smart Citation

Unusual properties of thermally sensitive oligomer-enzyme conjugates of poly(N-isopropylacrylamide)-trypsin

Ding¹,

Chen²,

Hoffman³

1998

J. Biomed. Mater. Res.

104

View full text Add to dashboard Cite

Reversible soluble-insoluble oligomer-enzyme conjugates have been prepared by conjugating a thermally sensitive oligomer, poly(N-isopropylacrylamide) [poly(NIPAAm)] to trypsin. The conjugates can catalyze enzymatic reactions in solution and then may be separated from the solution by thermal precipitation. One special feature of the conjugates is that every poly(NIPAAm) chain has only one end attachment to the enzyme, so that the loss of enzymatic activity due to steric hindrance should be minimized. Conjugates with various numbers of oligomer chains per trypsin molecule were prepared. Surprisingly, the conjugates increased in enzymatic activity with increasing oligomer conjugation to the native trypsin. The trypsin active sites in the conjugates were accessible to large molecules, such as soybean trypsin inhibitor (MW = 21,500). The enzyme conjugates were more stable than native trypsin, both in solution and in the precipitated phase. On the other hand, the conjugates lost enzymatic activity faster than native trypsin when the temperature was repeatedly cycled through the lower critical solution temperature (LCST) of the poly(NIPAAm). The recovery of the conjugates by thermal precipitation in each cycle was over 95% even after 14 cycles through the LCST.

show abstract

Section: Thermal Cyclingsupporting

confidence: 80%

“…Enzyme immobilization has been reviewed extensively. [4][5][6] The immobilized enzymes are readily separated from the reaction medium and usually have better stability at higher temperatures 7,8 and longer shelf life 9 than native enzymes.…”

Section: Introductionmentioning

confidence: 99%

Unusual properties of thermally sensitive oligomer-enzyme conjugates of poly(N-isopropylacrylamide)-trypsin

Ding¹,

Chen²,

Hoffman³

1998

J. Biomed. Mater. Res.

104

View full text Add to dashboard Cite

show abstract

“…In this latter case the high stability may be due to the very slight leakage of the immobilized enzyme compared with the former case. 17 Yang et al 18 reported that the enhanced stability of the polymer which incorporated subtilisin may be related to the decreased auto-hydrolysis of the enzyme. …”

Section: Reuse Efficiencymentioning

confidence: 98%

Pullulanase immobilization on natural and synthetic polymers

Dessouki

Issa²,

Atia³

2001

J of Chemical Tech & Biotech

View full text Add to dashboard Cite

This work describes the immobilization of pullulanase onto two different polymers; agarose activated with epichlorohydrin and trichlorotriazine and casein activated with epichlorohydrin, in addition to a synthetic copolymer, butylacrylate±acrylic acid (BuA/AAc). Immobilization by covalent binding yields stable enzyme activity. The operational stability of the free and immobilized enzymes showed that the enzyme immobilized by a crosslinking technique using glutaric dialdehyde (GA) showed poor durability and the relative activity decreased sharply due to leakage after repeated washing, while the enzymes immobilized by covalent bonds resulted in a slight decrease in most cases in the relative activity (around 20%) after being used 10 times. Storage for 4±6 months showed that the free enzyme lost most of its activity, while the immobilized enzyme showed the opposite behavior. Subjecting the immobilized enzymes to doses of g-radiation (0.5±10 Mrad) resulted in complete loss in the activity of the free enzyme at a dose of 5 Mrad, while the immobilized enzymes showed relatively high resistance to g-radiation up to a dose of 5 Mrad. Nuclear Magnetic Resonance ( 1 H NMR) and FTIR measurements were carried out to con®rm the structure of the polymer as well as the immobilization process of the enzyme onto the polymeric carrier. The unique biochemical characteristics, mode of action and utility of the environmentally compatible pullulanase in starch conversion are well known. Using pullulanase with b-amylase in starch sacchari®cation processes can increase maltose yield by 20±25%.

show abstract

“…Such significant increase could be primarily as a result of the enzyme stabilization, particularly the structural stabilization, that has occurred during the immobilization process (22).…”

Section: Discussionmentioning

confidence: 99%