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Synthesis and biochemical characterization of hybrid analogues of human insulin and IGF-2
Povalová, Anna ; Stiborová, Marie (advisor) ; Koberová, Monika (referee)
The ever-increasing occurrence of diabetes mellitus brings about the need for development of new therapeutic agents to provide adequate treatment for patients. An important element in this research area is elucidation how insulin works, mainly in connection with insulin-like growth factors (IGF-1 and IGF-2), which show significant structural homology to each other. In addition, their respective receptors - insulin receptor (IR) and receptor for IGF-1 and IGF-2 (IGF-1R) - exhibit very high similarity. As a result, IGF-1 and IGF-2 can bind to IR and insulin can bind to IGF-1R. Of a particular importance is the high affinity binding of IGF-2 to the isoform A of IR. Unlike insulin, which predominantly mediates glucose entry into cells, IGFs induce growth or mitogenic effects. The finding which structural determinants in insulin and IGFs are responsible for the differences in the activation of their cognate receptors could provide an explanation for different functional responses upon binding of these hormones to different target cells. Understanding of this mechanism could also help in the development of functionally selective analogues of these hormones. The aim of this study was the synthesis and characterization of analogues of human insulin extended at the C terminus of the B chain with the amino...
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Preparation of a new insulin analog in order to study the interaction of the hormone with insulin receptor isoforms,
Halamová, Tereza ; Jiráček, Jiří (advisor) ; Obšilová, Veronika (referee)
Insulin acts as a key hormone in the blood glucose levels maintaining mechanisms. Outside this metabolic function it also has a growth hormone functionality. The interaction of insulin with the two existing insulin receptor isoforms - IR-A and IR-B, which are variously represented in the human body is determining insulin. IR-A, supposed to be mainly responsible for the mitogenic function of insulin, is located in the brain or lymphatic cancer and fetal tissue, whereas IR-B, performing metabolic function is located in adipose and muscle tissue. Present aim is to design such insulin analogs that would preferentially bind to IR-B, and could thus more efficiently carry out physiological metabolic function of insulin necessary for patients with diabetes. Based on the recently solved 3D structure of insulin bound to IR, it was found that the C-terminus of the B-chain of insulin must undergo conformational change bending it in about 90ř, for efficient binding to IR. The aim of this thesis was the preparation and characterization of two insulin analogs with bridging C-terminus of the B-chain in positions B26-B29 and B27-B29 using disulfide bridge. This could fix a bended structure of the B chain end and could help to increase the affinity of IR and specificity for IR-B. The preparation was carried out...
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Preparation and characterization of selective analogues of insulin and IGF-II for various isoforms of the insulin receptor
Křížková, Květoslava ; Stiborová, Marie (advisor) ; Obšilová, Veronika (referee)
Modern lifestyle with its lack of exercise and healthy diet often leads to obesity which is accompanied by a decreasing biological effect of insulin and the onset of hyperinsulinemia, and consequently type 2 diabetes. Persistently high levels of insulin stimulate signalling pathways with growth effects; cells thus become more sensitive to mitogenic effects of all growth factors which may even lead to the loss of control over cell proliferation and the rise of various malignancies. Due to a high degree of structure homology of insulin, IGF-I/II as well as particular IR (existing in "mitogenic" IR-A isoform and "metabolic" IR-B isoform) and IGF-1R, there are a number of cross- interaction among hormones and receptors; nevertheless, the biological response may be different during the binding to a receptor. The determination of the crucial structural regions in insulin and IGF which are responsible for binding to the receptors could lead to the evolution of selective insulin analogues with strengthen metabolic effects, or could lead to the evolution of selective antagonism of IGF which would, in turn, suppress the mitogenic effect. The highest overlap is between insulin and IGF-II since both hormones are able to bind to the isoform A of an insulin receptor (IR-A) with a high affinity, and to activate...
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Synthesis and biochemical characterization of hybrid analogues of human insulin and IGF-2
Povalová, Anna ; Stiborová, Marie (advisor) ; Koberová, Monika (referee)
The ever-increasing occurrence of diabetes mellitus brings about the need for development of new therapeutic agents to provide adequate treatment for patients. An important element in this research area is elucidation how insulin works, mainly in connection with insulin-like growth factors (IGF-1 and IGF-2), which show significant structural homology to each other. In addition, their respective receptors - insulin receptor (IR) and receptor for IGF-1 and IGF-2 (IGF-1R) - exhibit very high similarity. As a result, IGF-1 and IGF-2 can bind to IR and insulin can bind to IGF-1R. Of a particular importance is the high affinity binding of IGF-2 to the isoform A of IR. Unlike insulin, which predominantly mediates glucose entry into cells, IGFs induce growth or mitogenic effects. The finding which structural determinants in insulin and IGFs are responsible for the differences in the activation of their cognate receptors could provide an explanation for different functional responses upon binding of these hormones to different target cells. Understanding of this mechanism could also help in the development of functionally selective analogues of these hormones. The aim of this study was the synthesis and characterization of analogues of human insulin extended at the C terminus of the B chain with the amino...
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