The remaining 10% in the body of Polygraph Polygraphovich Sharikov are human organs (transplanted pituitary and seminal glands). The donor was a bandit, thief and alcoholic killed in a fight. A typical gopnik, as an example.
So Edward will have a lot of... fun living with him!
If you thought that Comrade Sharikov and Mr. Hyde were similar in character and appearance, then... you're right. Read these novels and see for yourself. BUT! Recently, while replaying the plot of both stories in my head, I noticed another similarity. Namely, the division of living space. Damn documents, papers! Without them, there would be no conflict in the stories.