PKA Inhibitor Fragment (6-22) amide TFA

PKA inhibitor fragment (6-22) amide TFA is a synthetic peptide inhibitor of cAMP-dependent protein kinase A (PKA) with K_i=1.7 nM. PKA inhibitor fragment (6-22) amide TFA is derived from the thermostable PKA inhibitor protein PKI and is the shortest synthetic PKI peptide that retains potent PKA inhibitory activity^[1]. Both the arginine pseudosubstrate site at the COOH-terminus of the PKI peptide and the NH₂-terminal residue Phe¹⁰ are required for this efficient inhibition^[2].

PKA inhibitor fragment (6-22) amide TFA (20 μM) can reverse the increase in cAMP level and PN-1 mRNA expression in AtT-20 cells induced by serine protease inhibitors^[3]. Moreover, 10 μM PKA inhibitor fragment (6-22) amide TFA can also promote lactate dehydrogenase (LDH) release in human fibroblasts (WS1) and human keratinocytes (HaCaT) cells^[4].

References:
[1] Glass, D.B., Cheng, H.C., Mende-Mueller, L., et al.Primary structural determinants essential for potent inhibition of cAMP-dependent protein kinase by inhibitory peptides corresponding to the active portion of the heat-stable inhibitor proteinJ. Biol. Chem.264(15)8802-8810(1989)
[2] Glass, D.B., Lundquist, L.J., Katz, B.M., et al.Protein kinase inhibitor-(6-22)-amide peptide analogs with standard and nonstandard amino acid substitutions for phenylalanine 10. Inhibition of cAMP-dependent protein kinaseJ. Biol. Chem.264(24)14579-14584(1989)
[3] Hisatsugu Koshimizu, Niamh X. Cawley, Taeyoon Kim, Alfred L. Yergey, Y. Peng Loh, Serpinin: A Novel Chromogranin A-Derived, Secreted Peptide Up-Regulates Protease Nexin-1 Expression and Granule Biogenesis in Endocrine Cells, Molecular Endocrinology, Volume 25, Issue 5, 1 May 2011, Pages 732–744.
[4] Yang T, Geng F, Tang X, et al. UV radiation‐induced peptides in frog skin confer protection against cutaneous photodamage through suppressing MAPK signaling[J]. MedComm, 2024, 5(7): e625.

PKA inhibitor fragment (6-22) amide TFA是一种cAMP依赖性蛋白激酶A（PKA）的合成肽抑制剂，K_i=1.7 nM。PKA inhibitor fragment (6-22) amide TFA源自热稳定的PKA抑制剂蛋白PKI，它是最短的合成PKI肽，保留了高效的PKA抑制作用^[1]。PKI肽COOH末端的精氨酸假底物位点和NH₂末端的残基Phe¹⁰ 都是这种高效抑制作用所必需的^[2]。

PKA inhibitor fragment (6-22) amide TFA（20μM）可以逆转丝氨酸蛋白酶抑制剂引起的AtT-20细胞中 cAMP水平升高和 PN-1 mRNA表达增加^[3]。并且，10 μM PKA inhibitor fragment (6-22) amide TFA还可以促进人成纤维细胞（WS1）和人角质形成细胞（HaCaT）细胞的乳酸脱氢酶 (LDH) 释放^[4]。