Stability of prolin-containing peptides in biological media

Abstract

New data on peptide drugs have been summarized; their high stability is due to both the introduction of Pro-Gly-Pro in various amino acid sequences and the modification of the glyproline fragment itself. Pro-Gly-Pro-Leu, ACTH(6-9)Pro-Gly-Pro, 5-oxo-Pro-Arg-Pro and 5-oxo-Pro-His-Pro-NH2 were used as proline-containing peptides. Tritiated peptides were obtained: Pro-Gly-Pro-Leu with specific radioactivity of 135 Ci/mmol, ACTH(6-9)Pro-Gly-Pro – 26 Ci/mmol, 5-oxo-Pro-Arg-Pro – 60 Ci/mmol and 5-oxo-Pro-His-Pro-NH2 – 75 Ci/mmol. The concentration of Pro-Gly-Pro-Leu, ACTH(6-9)Pro-Gly-Pro, 5-oxo-Pro-Arg-Pro and 5-oxo-Pro-His-Pro-NH2 in the blood was found to be about 200 times more than in the brain for intranasal administration, and in average 600 times more for intravenous administration. The stability of proline-containing peptides in vitro experiments was determined using different commercially available peptidases (leucine aminopeptidases, dipeptidases, carboxypeptidases B and Y), and using nasal mucus, microsomal fraction of the rat brain (IMPC) and rat blood plasma. During peptidase hydrolysis of Pro-Gly-Pro-Leu, the main metabolites were Gly-Pro-Leu, Pro-Gly-Pro, Gly-Pro and Pro-Gly. For ACTH(6-9)Pro-Gly-Pro, the main metabolites were Phe-Arg-Trp-Pro-Gly-Pro and Trp-Pro-Gly-Pro. In peptidase hydrolysis of 5-oxo-Pro-His-Pro-NH2, the major metabolite was 5-oxo-Pro-His-Pro. It was shown that with different methods of peptides administration the composition of the metabolites formed is different. Based on the data obtained, resistance to enzymatic cleavage of peptides and their metabolic pathways were evaluated. Thus, these new data have shown that the above approaches can be used to prolong the action of glyprolines in living objects. In this case, the degradation of proline-containing peptides occurs mainly not due to the action of proteases, but due to other ways of degradation. In general, the data presented in the review indicate the promise of intranasal way of introducing biologically active peptides into the brain of living organisms.

Non-hematopoietic erythropoietin-derived peptides for atheroprotection and treatment of cardiovascular diseases

“…In parallel, the PGP motive (Pro-Gly-Pro) was added to a number of compounds to improve their pharmacokinetic characteristics. This amino acid sequence stabilizes the molecule in biological media by inhibiting the activity of proteolytic enzymes (Shevchenko et al 2019). Moreover, PGP also has the ability to block the angiotensin-converting enzyme (Wang et al 2011), one of the most important proatherogenic factors that catalyzes the reaction of angiotensin II formation and promotes vascular wall remodeling (Montezano et al 2014).…”

11-amino acid peptide imitating the structure of erythropoietin α-helix b improves endothelial function, but stimulates thrombosis in rats.

“…[23][24][25]. Кроме того, Pro-Gly-Pro стабилизирует молекулу в биологических средах за счет ингибирования активности протеолитических ферментов [26] и обладает способностью блокировать ангиотензин-превращающий фермент [27], один из важнейших проатерогенных факторов, который катализирует реакцию образования ангиотензина II и способствует ремоделированию сосудистой стенки [28]. Ключевым вопросом остается характер (позиция, линкеры и т.д.)…”

Erythropoietin Mimetic Peptide (pHBSP) Corrects Endothelial Dysfunction in a Rat Model of Preeclampsia

“…In parallel, the PGP Tripeptide (Pro-GlyPro) can be added to improve the pharmacokinetic characteristics. This amino acid sequence stabilizes the molecule in biological environments by inhibiting the activity of proteolytic enzymes [ 49 ]. Moreover, PGP can also block the angiotensin-converting enzyme [ 50 ], one of the most important pro-atherogenic factors that catalyze the formation of angiotensin II, increasing the risk of brain stroke [ 51 ].…”