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.
Laboratory for Food Science, Gakushuin Women's Junior College, Tokyo.
M
M
Abe
K
K
Abe
K
K
Iwabuchi
C
C
Domoto
S
S
Arai
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