Involvement of SDS-stable higher M(r) forms of bovine normal milk alpha-lactalbumin in inducing intestinal IEC-6 cell death.
Monomeric 14-kDa bovine alpha-lactalbumin was purified with a preparation of lower molecular weight whey protein concentrate from Holstein cow normal milk followed by size exclusion chromatography. The protein showed a stimulatory rather than an inhibitory effect on the proliferation of a cultured IEC-6 cell line from the rat small intestine. But incubation in 30% trifluoroethanol/acetate buffer (pH 5.5) at 37 degrees C for 5 d in a slowly rotating test tube rendered it highly cytotoxic with concomitant appearance of SDS-stable 20- and 30-kDa forms of alpha-lactalbumin on electrophoresis. Furthermore, alpha-lactalbumin obtained by a one-step purification procedure by affinity chromatography on an anti-alpha-lactalbumin antibody column from the lower molecular weight whey protein concentrate, which had been found to contain several SDS-stable higher M(r) forms of alpha-lactalbumin, exhibited potent inhibitory activity on IEC-6 cell growth. These results indicate the involvement of SDS-stable higher M(r) forms of bovine normal milk alpha-lactalbumin in inducing cell death on the intestinal IEC-6 cell line.
Department of Food Science, Faculty of Applied Biological Science, Gifu University, Japan.
Meiyu
M
Xu
Yoshimasa
Y
Sugiura
Satoshi
S
Nagaoka
Yoshihiro
Y
Kanamaru
D000818:Animals; D002417:Cattle; D016923:Cell Death / Q000187:drug effects*; D002460:Cell Line; D007413:Intestinal Mucosa / Q000166:cytology / Q000187:drug effects*; D007768:Lactalbumin / Q000737:chemistry / Q000302:isolation & purification / Q000633:toxicity*; D008970:Molecular Weight; D020033:Protein Isoforms
D020033:Protein Isoforms; D007768:Lactalbumin