Rewrite the following paragraph by writting most appropriate words in the blank places.
Insulin is a....... hormone produced by beta cells of islets of Langerhans of pancreas, insulin is essential for the control of blood sugar levels......... is a disease in which some people cannot make insulin themselves. Hakura et al, chemically synthesized DNA sequence of insulin for two chains....... and separately inserted into two....... vector. Insulin production by recombinant DNA technology is designed by Gilbert and Villa -Komaroff. The genes are inserted by the side of ..... gene of the plasmid. The recombinant plasmids were then separately transformed into E. coil host. The host produced penicillinase + pre-pro insulin . Insulin is later separated by ......... treatment.