Catalytic properties of enzymes modified with temperature-responsive polymer chains

✍ Scribed by Hitomi Nagayama; Yasushi Maeda; Choichiro Shimasaki; Hiromi Kitano

• Publisher: John Wiley and Sons
• Year: 1995
• Tongue: English
• Weight: 515 KB
• Volume: 196
• Category: Article
• ISSN: 1022-1352
• DOI: 10.1002/macp.1995.021960216

✦ Synopsis

Abstract

Temperature‐responsive changes in catalytic properties of enzymes modified with a temperature‐responsive polymer, poly(N‐isopropylacrylamide) (PIPA), were examined. PIPA with a carboxyl group at its end was prepared using 2,2′‐azoisobutyronitrile as initiator in the presence of 3‐mercaptopropionic acid as a chain transfer reagent. After being activated by the coupling with N‐hydroxysuccinimide, PIPA was directly bound to enzymes such as acid phosphatase and trypsin. The catalytic activities of the modified enzymes showed a bending point in their Arrhenius plots at about 33°C due to a coil‐globule transition of PIPA chains. The ratio of amidase‐ and esterase‐activities of trypsin modified with PIPA chains was largely affected by the changes in temperature. As for the semi‐enzymatic synthesis of N‐benzoyl‐L‐arginylglycinamide, secondary hydrolysis of the peptide product observed with free trypsin was effectively suppressed in modified trypsin at 45°C (above the transition temperature), and the peptide was obtained with higher conversion.