ABSTRACT
Aminopeptidase A (Pep A) is a metal-dependent enzyme that specifically hydrolyze peptides with the N-terminal amino acids glutamic acid (Glu) and aspartic acid (Asp). A possible application of PepA is the hydrolysis of Glu/Asp-rich food proteins such as wheat gluten and casein, increasing the flavor and solubility of food protein. In the present study, the gene encoding a Pep A from Lactococcus lactis ssp. lactis IL1403 was synthesized and introduced into Pichia pastoris GS115 (His4). Lc-Pep A was successfully expressed and secreted to the culture medium, followed by identification and purification to homogeneity. Characteristics study demonstrated that Lc-Pep A could specifically hydrolyze the substrates Glu-pNA and Asp-pNA with similar catalytic activity, and this was further confirmed by the kinetics parameters measured. Additionally, Lc-Pep A showed a broad thermostability and pH stability with an optimum temperature of 60 ℃ and an optimum pH of 8.0. The enzyme activity of Lc-Pep A was activated by metal ions Co2+, Mn2+, and Zn2+ but was strongly inhibited by Ni2+and Cu2+. The routine proteinase inhibitor had no effect on the activity of Lc-Pep A. However, Lc-Pep A was strongly inhibited by the metallopeptidase inhibitor, EDTA, and disulfide bond-reducing agents. The study may facilitate production and application of Lc-Pep A.
Subject(s)
Glutamyl Aminopeptidase , Lactococcus lactis/genetics , Biological Transport , Culture Media , Glutamic AcidABSTRACT
Hypertension is one of the most important risk factors for the development of ischemic heart diseases, stroke, disability, vascular demen?a, heart failure, renal dysfunc?on, re?nopathy, and premature death. Despite the use of two or more blood pressure lowering medica?ons, a considerable propor?on of pa?ents show poor control. Current an?hypertensive medica?ons show the limita?on of use and effect in obese popula?on, certain races like black popula?on and also in renal impairment. Thus, there is an impending need to develop novel classes of an?hypertensive agents ac?ng on new targets with diversified mechanisms of ac?on to more effec?vely manage raised blood pressure. With the introduc?on of the recent concept of overac?ve brain renin angiotensin system in cardiovascular disorders, a?empts have been made to iden?fy a molecule with the poten?al of inhibi?ng aminopep?dases involved in the forma?on of Angiotensin III. A novel aminopep?dase A inhibitor, also a prodrug Firibastat is currently undergoing development in Phase III clinical trials for hypertension as well as chronic heart failure. We hereby, provide an updated summary of evidence generated so far with Firibastat and also a glimpse into the therapeu?c poten?al of this novel candidate extending beyond the spectrum of essen?al hypertension
ABSTRACT
ObjectiveTo study the correlation between essential hypertension and plasma aminopeptidase A.MethodsThe people of the Han nationality in Huainan city received questionnaire investigation and their blood pressure,height and weight were measured.131 individuals suffered from hypertension and 134 healthy individuals belongs to hypertensive pedigree and 127 individuals suffered from hypertension and 132 healthy individuals belongs to non-hypertensive pedigree were reseached.The level of Ang Ⅱ in plasma was detected by RIA,and the level of APA was detected by ELISA.ResultsThe levels of Ang Ⅱ and APA in plasma in HP group was significantly higher than that in NHP group in two pedigrees ( t =10.3398,6.5613,11.7089,6.6683,all P ＜ 0.01 ).Furthermore,the levels of Ang Ⅱ and APA in plasma in HP group in hypertensive pedigree was significantly higher than that in HP group in nonhypertensive pedigree(t =3.6201,6.1091,all P ＜ 0.01 ).There was significantly positive correlation between MAP and the levels of Ang Ⅱ and APA in plasma in HP group in two pedigrees ( r =0.315,0.392,all P ＜ 0.05 in non-hypertensive pedigree,and r =0.412,0.505,all P ＜ 0.01 in hypertensive pedigree ).There was positive correlation between the levels of Ang Ⅱ and APA in plasma in HP group in hypertensive pedigree ( r =0.322,P ＜ 0.05 ).ConclusionThere was significant difference between hypertensive pedigree and non-hypertensive pedigree in the levels of APA;The levels of APA in plasma in HP group was significantly increased in the individuals suffered from hypertension,and was positively correlated with MAP.