Receptor gene cloning, insulin

Insulin receptor gene cloned and mapped to chromosome 19p 13.2-13.3 5... 

Using directed mutation of the cloned receptor gene, Lys 1018 in the ATP-binding part of the tyrosine kinase domain was replaced by alanine. This caused a loss both of kinase activity and of biologic response to insulin.362 Thus, both the tyrosine kinase activity and autophosphorylation appear essential. If so, aggregation of two or more receptors may increase the extent of autophosphorylation and initiate a response. 

If a single gene is cloned in sufficient quantity, it can be sequenced (see Deoxyribonucleic acid) and the amino acid sequence of the gene product can be predicted from the nucleotide sequence of the DNA. For example, the amino acid sequences of the insulin receptor, nicotinic and muscarinic cholinergic acetylcholine receptors, epidermal growth factor precursor and many (thousands) other proteins have been predicted in this way. 

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