Sentence:  There is some reason to think that thyroglobulin synthesis may proceed independently of iodination , for in certain transplantable tumours of the rat thyroid containing essentially no iodinated <WSD>thyroglobulin</WSD> , a protein that appears to be thyroglobulin has been observed in ultracentrifuge experiments ( Wolff , Robbins and Rall , 1959 ) . 
Meaning of the word marked with <WSD> tags:  an iodine containing protein that is obtained from the thyroid gland and exhibits the general properties of the globulins