Human [Ala31] IGF-I

Human [Ala31]insulin-like Growth Factor-I ([Ala31]IGF-I) is an analogue of human IGF-I which has an Alanine substitution in place of Tyrosine at position 31 of the human IGF-I sequence. [Ala31]IGF-I has normal binding to acid-stripped human serum binding proteins but has reduced binding to the type 1 IGF receptor and to the insulin receptor compared to IGF-I. It has a slightly higher affinity for the type 1 IGF receptor than [Leu24]IGF-I and [Leu60]IGF-I and is able to elicit a weak biological response through this receptor. It is a useful analogue for studying the balance of effects of IGF-I through the type 1 receptor and IGF binding proteins.