Potent, high affinity apelin receptor agonist (IC50 = 0.27 nM; Kd = 0.51 nM). Exhibits no binding GPR15 and GPR25. Activates the PI3K/AKT pathway and promotes self-renewal of hESCs via cell-cycle progression and protein translation. Also potentiates the TGFβ pathway, priming hESCs toward the endoderm lineage. Stimulates angiogenesis in HUVEC cells. Relaxes mouse aortic vessels. Functions as an anorexigenic hormone through activation of the AVP and CRH neurons in the PVN.

HR1 是一种乳突蛋白酶。HR1 能增加人红细胞膜的渗透性。 HR1 能诱导细菌的细胞质膜透化，还能诱导肥大细胞的质膜透化。

D-脯氨酸是天然氨基酸 L-脯氨酸的异构体。已发现人血浆和唾液中的 D-氨基酸含量相对较高。这些氨基酸可能源自细菌，但也有证据表明它们是通过氨基酸消旋酶活性内源产生的。