Human Long Arg3 Insulin-like Growth Factor-I (Long-R3-IGF-I) is an 83 amino acid analog to human IGF-I. It has the complete human IGF-I sequence with the substitution of Arg for Glu at position 3 (hence R3), and a 13 amino acid extension at the N-terminus.
IGF-1 Long R3 is a synthetic analog of the naturally existing insulin growth factor (IGF) which is a 93 amino acid residue. Modifications of the natural form occurred with the substitution of the Arg with Glu at the position 3, giving a code R3, and also an extension of a 13 amino acid at the B-terminus. Just like the IGF-1, R3 has been shown to induce the development and growth of cells.
Long R3 IGF-1 is significantly more potent than IGF-1. The enhanced potency is due to the decreased binding of Long R3 IGF-1 to all known IGF binding proteins. These binding proteins normally inhibit the biological actions of IGF's. When IGF is active it behaves differently in different types of tissues. In muscle cells proteins and associated cell components are stimulated. Protein synthesis is increased along with amino acid absorption. As a source of energy, IGF mobilizes fat for use as energy in adipose tissue. In lean tissue