Bovine lactoferrin was separated into lactoferrin-a and lactoferrin-b from
bovine colostrum. Lactoferrin-a was eluted at 0.38 M NaCl and lactoferrin-b
was eluted at 0.43 M NaCl by carboxymethyl cation-exchange chromatography
at pH 7.7, 0.05 M phosphate buffer. The molecular weights were estimated at
84,000 for lactoferrin-a and 80,000 for lactoferrin-b. Lactoferrin-a conte
nts were 258.0 mg/L and lactoferrin-b contents were 524.3 mg/L of colostrum
for cow 19. From colostrum to normal milk, total lactoferrin was from 17.1
to 129.4 mg/L during the normal lactational period; however, lactoferrin d
id not separate clearly into lactoferrin-a and lactoferrin-b. The lactoferr
in-a measured from six cows was 258.0, 114.0, 112.8, 64.0, 59.7, and 22.4 m
g/ L and the lactoferrin-b 524.3, 331.8, 184.7, 170.7, 129.3, and 44.0 mg/L
, respectively. The average was 105.2 mg (31.3%) for lactoferrin-a and 230.
8 mg (68.7%) for lactoferrin-b.