The presence of a novel cellular retinoic acid-binding protein in chick embryos: purification and partial characterization.

Two cellular retinoic acid binding proteins, CRABP I and II, which behaved differently on a DEAE-cellulose column, were purified from 14-day chick embryos. Their molecular weights were 15.8 kDa and 16.2 kDa, respectively. NH2-terminal 36 amino acid sequence of CRABP I was identical to that of bovine CRABP, which was reported previously. CRABP II was a novel cellular retinoic acid binding protein, in which the amino acids at 6 positions of the NH2 terminal sequence are different from those in CRABP I. The homology between CRABP I and II was more than 83%.