Identification and characterization of cathepsin D in a highly purified sialidase from starfish A. pectinifera.
A sialidase [EC 3.2.1.18] from the ovary of starfish Asterina pectinifera was isolated and highly purified by preparative PAGE. The SDS-PAGE separation of the purified enzyme revealed two natures of protein bands, upper (50 kDa) and a lower (47 kDa). To identify the protein, N-terminal amino acid sequence of the upper band was done. The sequence matched with the N-terminal amino acid sequence of human lysosomal mature cathepsin D and cathepsin D activity was also found in all the preparation steps. Protease inhibitor pepstatin A inhibited the proteolysis activity of cathepsin D against a synthetic substrate. The two enzymes sialidase and cathepsin D were separated from each other by using high-performance gel-filtration chromatography. The Western blot analysis and isoelectric focusing showed the co-purified cathepsin D is a 50 kDa protein with a PI value of 4.2.
Kannappan
Ramaswamy
R
Department of Health Chemistry, Faculty of Pharmaceutical Sciences, Niigata University of Pharmacy and Applied Life Sciences, Niigata 956-8603, Japan.
Satoh
Youichi
Y
Iriyama
Naoko
N
Ando
Masayuki
M
Sawada
Michiko Takagi
MT
Takahashi
Nobuaki
N
Furuhata
Kimio
K
Uda
Yutaka
Y
D000595:Amino Acid Sequence; D000818:Animals; D047288:Asterina / Q000201:enzymology*; D002402:Cathepsin D / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D008969:Molecular Sequence Data; D009439:Neuraminidase / Q000302:isolation & purification* / Q000378:metabolism; D011480:Protease Inhibitors / Q000494:pharmacology; D017386:Sequence Homology, Amino Acid
D011480:Protease Inhibitors; D009439:Neuraminidase; D002402:Cathepsin D