CJC-1295 DAC peptides are a synthetic modification of GRF – the growth hormone releasing factor with substitutions at various positions. CJC-1295 with DAC increases the half life of the factor and also presents a high binding affinity for albumin.
CJC-1295 is a synthetic modification of growth hormone releasing factor (GRF) with D-Ala, Gln, Ala, and Leu substitutions at positions 2, 8, 15, and 27 respectively. These substitutions create a much more stable peptide with the substitution at position 2 to prevent DPP-IV cleavage, position 8 to reduce asparagine rearrangement or amide hydrolysis to aspartic acid, position 15 to enhance bioactivity, and position 27 to prevent methionine oxidation.
By applying the Drug Affinity Complex (DAC) technology to GRF, the peptide selectively and covalently binds to circulating albumin after subcutaneous (SC) administration, thus prolonging its half-life. These substitutions are key in increasing the overall half life of CJC-1295 but there lies an even greater reason as to why the half life has been extended from ~7 minutes to greater than 7 days!
Bioconjugation is a relatively newer technology that takes a reactive group and attaches it to a peptide, which in turn reacts with a nucleophilic (usually a partially negative molecule) entity found in the blood to form a more stable bond. Albumin, one of the most abundant substances in the human body is chosen as the nucelophile by this particular peptide thanks to a Cys34 thiol group that attracts it.
By combining the tetrasubstituted GHRH analogue with maleimodoproprionic acid using a Lys linker, you create a GHRH peptide with a high binding affinity for albumin. Once the CJC-1295 molecule has attached itself to albumin, it is given an extended half life and bioavailability thanks to the albumin preventing enzymatic degredation and kidney excretion. In fact, bioconjugation is so effective that there was less than 1% of CJC-1295 left unreacted in vivo and over 90% was stabilized after subcutaneous injection.
This means that you get more of what you paid for working for you. There was no DPP-IV degredation observed on CJC-1295 in any of the various experiments conducted.