Enzyme and Nonenzyme Hydrolyses of End Ester Group in Polyethylene Glycol Esters

Ouchi, Tatsuro; Azuma, Taiji

doi:10.1080/00222338408056574

Cited by 5 publications

(1 citation statement)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In contrast to HPMA copolymer-based substrates bearing chymotrypsin-cleavable oligopeptide pnitroanilide residues fixed as pendant groups, the substrate 6 contains the enzymatically cleavable residue as an end group. The differences between these two types of substrates were previously discussed in the literature (36,38). Our results are in agreement with the previously made observation that the end-group type of substrate is expected to be the more reactive one (36).…”

Section: Resultssupporting

confidence: 93%

Enzymic activity of chymotrypsin and its poly(ethylene glycol) conjugates toward low and high molecular weight substrates

Chiu¹,

Zalipsky²,

Kopečková³

et al. 1993

Bioconjugate Chem.

View full text Add to dashboard Cite

Native chymotrypsin and its polyethylene glycol (PEG) conjugates, obtained using the succinimidyl carbonate of methoxy-PEG (SC-PEG) as the amino group modifying reagent, were tested for their activity toward several low and high molecular weight substrates. Tripeptide and tetrapeptide p-nitroanilides either as N alpha-benzyloxycarbonyl derivatives or attached via their N-terminals to N-(2-hydroxypropyl)methacrylamide (HPMA) copolymers or to PEG, as well as the proteins albumin and azoalbumin, were used as substrates. Extensively modified chymotrypsin bearing on average of 14 PEG chains per chymotrypsin molecule (PEG14CHT) and a moderately modified one containing 10 PEG chains (PEG10CHT) both degraded the low molecular weight p-nitroanilides at rates comparable to, and in the case of PEG10CHT, greater than, the rates exhibited by the native enzyme. Synthetic high molecular weight substrates and azoalbumin were also degraded by the PEG-modified enzymes. However, rates of such enzymatic reactions were lower for the PEG-enzymes than for the native one. Native albumin, as compared to azoalbumin, resisted degradation by both PEGCHTs yet was readily digested by the native chymotrypsin. The results obtained indicate that substrate-size-dependent specificity of PEG-modified enzymes cannot be explained solely by steric hindrance considerations. The decreased activity of PEG-enzymes toward protein substrates is consistent with the well-documented ability of PEG to exclude proteins from its surroundings and with the influence of protein unfolding on the susceptibility to degradation.

show abstract

Section: Resultssupporting

confidence: 93%

Enzymic activity of chymotrypsin and its poly(ethylene glycol) conjugates toward low and high molecular weight substrates

Chiu¹,

Zalipsky²,

Kopečková³

et al. 1993

Bioconjugate Chem.

View full text Add to dashboard Cite

show abstract

Enzyme in der organischen Synthese

1985

View full text Add to dashboard Cite

Enzyme haben als Katalysatoren in der organischen Synthese eine grol3e Zukunft. Bisher sind ihre Anwendungen auf einige industriell in groDem MaRstab durchgefiihrte Hydrolysen sowie die Herstellung zahlreicher Reagentien fur Analysen und Synthesen im Laboratoriumsmahtab beschrankt. Verbesserungen bei der Produktion von Enzymen, die zum einen auf neuen Erkenntnissen der klassischen Mikrobiologie und zum anderen auf ersten erfolgversprechenden Ansatzen der Gentechnologie beruhen, sowie bei ihrer Stabilisierung und Handhabung machen diese Katalysatoren fur einen Gebrauch in der organischen Synthese immer attraktiver. Dieser Aufsatz beschreibt den aktuellen Stand auf dem sich schnell entwickelnden Gebiet der enzymkatalysierten organischen Synthese; daneben werden auch die Entwicklungsmoglichkeiten erortert.

show abstract

Enzymes as Catalysts in Synthetic Organic Chemistry [New Synthetic Methods (53)]

Whitesides

Wong

1985

Angew. Chem. Int. Ed. Engl.

449

View full text Add to dashboard Cite

Pages 61 7-71 8 New Synthetic Methods (53)Enzymes have great potential as catalysts for use in synthetic organic chemistry. Applications of enzymes in synthesis have so far been limited to a relatively small number of largescale hydrolytic processes used in industry, and to a large number of small-scale syntheses of materials used in analytical procedures and in research. Changes in the technology for production of enzymes (in part attributable to improved methods from classical microbiology, and in part to the promise of genetic engineering) and for their stabilization and manipulation now make these catalysts practical for wider use in large-scale synthetic organic chemistry. This paper reviews the status of the rapidly developing field of enzyme-catalyzed organic synthesis, and outlines both present opportunities and probable future developments in this field.

show abstract

Enzyme and Nonenzyme Hydrolyses of End Ester Group in Polyethylene Glycol Esters

Cited by 5 publications

References 6 publications

Enzymic activity of chymotrypsin and its poly(ethylene glycol) conjugates toward low and high molecular weight substrates

Enzymic activity of chymotrypsin and its poly(ethylene glycol) conjugates toward low and high molecular weight substrates

Enzyme in der organischen Synthese

Enzymes as Catalysts in Synthetic Organic Chemistry [New Synthetic Methods (53)]

Contact Info

Product

Resources

About