Isolation and characterization of a hydroxyproline-containing protein from soluble extracts of the leaves of sandal (Santalum album L.).

1. A hydroxyproline-containing protein was isolated from the soluble fraction of sandal leaves (Santalum album L.) and the purified protein was homogeneous by disc electrophoresis. 2. It is a glycoprotein containing 16% carbohydrate, the components of which were mainly arabinose, with only small amounts (about 5%) of galactose. The principal amino acids were glutamic acid, aspartic acid, glycine, alanine, arginine, lysine, proline and hydroxyproline, which together comprised 60% of the total. The number of acidic amino acids exceeds the number of basic amino acids. By Sephadex gel filtration, the approximate molecular weight was found to be about 63000. The ratio of residues of hydroxyproline to those of arabinose was 1:2. 3. The native protein is resistant to the action of several proteolytic enzymes. After partial hydrolysis with 0.1m-HCl, the protein became susceptible to attack by Pronase but remained resistant to collagenase.