Corn cystatin I expressed in Escherichia coli: investigation of its inhibitory profile and occurrence in corn kernels.
Corn cystatin I was expressed in Escherichia coli as a mature protein. It was purified by gel filtration on Sephadex G-50, ion-exchange HPLC, and reversed-phase HPLC. The purified protein showed strong inhibitory activities against papain (Ki: 3.7 x 10(-8) M), and cathepsins H (Ki: 5.7 x 10(-9) M) and L (Ki: 1.7 x 10(-8) M), whereas it inhibited cathepsin B to a lesser extent (Ki: 2.9 x 10(-7) M). Western blot analysis using antibody raised against corn cystatin I revealed that in the corn kernel, the protein occurs with a molecular mass of approximately 13 kDa. Localization in the aleurone layer and embryo of the corn kernel was shown by immunostaining microscopy.
Abe
M
M
Laboratory for Food Science, Gakushuin Women's Junior College, Tokyo.
Abe
K
K
Iwabuchi
K
K
Domoto
C
C
Arai
S
S
D003001:Cloning, Molecular; D015891:Cystatins / Q000096:biosynthesis* / Q000235:genetics; D015853:Cysteine Proteinase Inhibitors / Q000096:biosynthesis* / Q000235:genetics; D004926:Escherichia coli; D010940:Plant Proteins / Q000096:biosynthesis* / Q000235:genetics; D011994:Recombinant Proteins / Q000096:biosynthesis; D003313:Zea mays
D015891:Cystatins; D015853:Cysteine Proteinase Inhibitors; D010940:Plant Proteins; D011994:Recombinant Proteins; C077834:cystatin protein, Zea mays