High impact information on ENPEP

• Immunopurification of sucrase-isomaltase, maltase-glucoamylase, aminopeptidase N and aminopeptidase A showed that these microvillar enzymes become sulfated [1].
• An acute exploration of aminopeptidase A active site was performed by a combinatorial approach using (3-amino-2-mercapto-acyl)dipeptides able to fit its S(1), S(1)', and S(2)' subsites [2].
• Hence, this compound is the first selective APA inhibitor reported, and as such, it should be an interesting probe to explore the physiological involvement of APA in the metabolism of neuropeptides like angiotensin II and CCK8 [3].
• The effect of monensin and colchicine on the biogenesis of aminopeptidase N (EC 3.4.11.2), aminopeptidase A (EC 3.4.11.7), dipeptidyl peptidase IV (EC 3.4.14.5), sucrase (EC 3.2.1.48)-isomaltase (EC 3.2.1.10) and maltase-glucoamylase (EC 3.2.1.20) was studied in organ-cultured pig small-intestinal explants [4].
• The fact that the enzymes before reaching the microvillar membrane were found in a Ca2+-precipitated membrane fraction (intracellular and basolateral membranes), but not in soluble form, indicates that during biogenesis maltase-glucoamylase, aminopeptidase A and dipeptidyl peptidase IV are transported and assembled in a membrane-bound state [5].

Biological context of ENPEP

• Screening of a rat genomic library with a partial rat APA cDNA resulted in isolation of a 12-kb clone found to contain the first exon and >3 kb of 5'-flanking sequence [6].
• Aminopeptidase-A (APA) has a widespread tissue distribution consistent with a role in the metabolism of circulating or locally produced ANG II or CCK-8 [6].

Anatomical context of ENPEP

• Aminopeptidase A (aspartate aminopeptidase, EC 3.4.11.7) was purified 2000-fold from pig kidney cortex [7].
• Cerebral microvascular aminopeptidase A may play a role in vivo in modulating angiotensin-mediated local cerebral blood flow, and in preventing circulating angiotensins from crossing the blood-brain barrier [8].
• Purification and characterization of an aminopeptidase A from hog intestinal brush-border membrane [9].
• APA is also highly expressed in pre-B lymphocytes, but its role in lymphoid cell development is unknown [6].
• On the other hand, APA and GGT were active in the epithelium and endothelium [10].

Associations of ENPEP with chemical compounds

• Aminopeptidase A was sensitive to inhibition by chelating agents and the inactive enzyme could be reactivated by Ca2+ or Mn2+ [7].
• The 2-naphthylamide derivatives of neutral and basic amino acids were also hydrolysed by aminopeptidase A, but at rates about two orders of magnitude lower, and Ca2+ was inhibitory [7].
• Differential inhibition of aminopeptidase A and aminopeptidase N by new beta-amino thiols [3].
• Aminopeptidase A (APA) is a highly selective peptidase, which cleaves the N-terminal Glu or Asp residues of biologically active peptides, and has therefore been proposed to be involved in angiotensin II and CCK8 metabolism [3].
• For aminopeptidase N (EC 3.4.11.2), aminopeptidase A (EC 3.4.11.7), sucrase-isomaltase (EC 3.2.1.48-10) and maltase-glucoamylase (EC 3.2.1.20), castanospermine caused the formation of novel transient forms of higher Mr than corresponding controls, indicating a blocked removal of glucose residues [11].

Other interactions of ENPEP

• The biogenesis of three intestinal microvillar enzymes, maltase-glucoamylase (EC 3.2.1.20), aminopeptidase A (aspartate aminopeptidase, EC 3.4.11.7) and dipeptidyl peptidase IV (EC 3.4.14.5), was studied by pulse-chase labelling of pig small-intestinal explants kept in organ culture [5].

References