Structure and Stability of the Potato Cysteine Protease Inhibitor Group (Cv. Elkana)
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- 作者：Laurice Pouvreau ; Toos Kroef ; Harry Gruppen ; Gerrit van Koningsveld ; Lambertus A. M. van den Broek ; and Alhons G. J. Voragen
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2005
- 出版时间：July 13, 2005
- 年：2005
- 卷：53
- 期：14
- 页码：5739 - 5746
- 全文大小：155K
- 年卷期：v.53,no.14(July 13, 2005)
- ISSN：1520-5118
文摘
The conformational stability of potato cysteine protease inhibitor (PCPI), the second most abundantprotease inhibitor group in potato tuber, was investigated at ambient temperature and upon heatingusing far- and near-UV circular dichroism spectroscopy, fluorescence spectroscopy, and differentialscanning calorimetry (DSC). The PCPI isoforms investigated have a highly similar structure at boththe secondary and the tertiary level. PCPI isoforms show structural properties similar to those of thepotato serine protease inhibitor group and the Kunitz type soybean trypsin inhibitor, a known 
-IIprotein. Therefore, PCPI isoforms are also classified as members of the -II protein subclass. Resultsshow that the thermal unfolding of PCPI isoforms does not follow a two-state mechanism and that atleast one intermediate is present. The occurrence of this intermediate is most apparent in the thermalunfolding of PCPI 8.3 as indicated by the presence of two peaks in the DSC thermogram. Additionally,the formation of aggregates (>100 kDa), especially at low scan rates, increases the apparentcooperativity of the unfolding.Keywords: PCPI; thermal unfolding; -II protein; aggregation
-IIprotein. Therefore, PCPI isoforms are also classified as members of the -II protein subclass. Resultsshow that the thermal unfolding of PCPI isoforms does not follow a two-state mechanism and that atleast one intermediate is present. The occurrence of this intermediate is most apparent in the thermalunfolding of PCPI 8.3 as indicated by the presence of two peaks in the DSC thermogram. Additionally,the formation of aggregates (>100 kDa), especially at low scan rates, increases the apparentcooperativity of the unfolding.Keywords: PCPI; thermal unfolding; -II protein; aggregation