Structural study of the sugar chains of CD36 purified from bovine mammary epithelial cells: Occurrence of novel hybrid-type sugar chains containing the Neu5Ac.alpha.2.fwdarw.6GalNAc.beta.1.fwdarw.4GlcNAc and the Man.alpha.1.fwdarw.2Man.alpha.1.fwdarw.3Man.alpha.1.fwdarw.6Man groups