Seminal Plasma Leucine Aminopeptidase in Male Fertility

Abstract

Summary: Leucine aminopeptidase (LAP) enzymatic activity has been measured in the seminal fluid of a group of 119 males undergoing fertility check‐up, and correlated with spermatic density. The results indicate that there exists a direct correlation between LAP activity in the seminal plasma and spermatic density. However, differences between the groups considered according to spermatic density are not significant. Seminal plasma mean Leucine aminopeptidase is 40 times higher than that found in blood plasma. Zusammenfassung: Die enzymatische Aktivität der Leucin‐Aminopeptidase (LAP) wurde im Spermaplasma bei einer Gruppe von 119 Männern, die sich einer Fertilitätsuntersuchung unterzogen, gemessen und in Beziehung zur Spermatozoendichte gesetzt. Die Ergebnisse zeigen, daß ein direkter Zusammenhang zwischen LAP‐Aktivität im Spermaplasma und der Spermatozoendichte besteht. Jedoch sind die Unterschiede zwischen den Gruppen, betrachtet nach der Spermatozoendichte, nicht signifikant. Der Durchschnittswert der LAP im Spermaplasma ist 40 mal höher als im Blutplasma.

A Unified Mechanism for Aminopeptidase N-based Tumor Cell Motility and Tumor-homing Therapy

“…First, integrins mediate cell motility and adhesion via binding to their signature RGD motifs in ECM proteins and on the surface of other cells. Like integrins, APN functions not only in tumor cell motility but also in other cell motility and adhesion processes such as immune cell chemotaxis, sperm motility, and monocytic cell adhesion (17)(18)(19)(20)(21)(22)(23). Here, we propose that APN mediates these other cell motility and adhesion processes by binding to its signature NGR motifs in ECM proteins and on the surface of other cells.…”

“…Thus, APN-mediated tumor cell motility and metastasis reside on some unknown activity of APN that is independent from its zinc-dependent aminopeptidase activity. In addition to mediating tumor cell motility, APN also functions broadly in other cell motility and adhesion processes such as immune cell chemotaxis, sperm motility, and monocytic cell adhesion (17)(18)(19)(20)(21)(22)(23). These functions of APN are reminiscent of those of integrins, which mediate cell motility and adhesion via specifically interacting with a three-residue motif, arginine-glycine-aspartate (RGD), in ECM proteins or on the surface of other cells (24 -28).…”

2,2′,4,4′-Tetrabromodiphenyl ether disrupts spermatogenesis, impairs mitochondrial function and induces apoptosis of early leptotene spermatocytes in rats

“…Defect in SUCLA2 gene results in reduction of mtDNA-content [29]. Lap3, a member of leucine aminopeptidase family that is positive relative to germ cells development and testicular tumor [37,38]. All these mitochondrial proteins are decreased in the testis of rats exposed to elevated BDE47 ( Fig.…”

Structural basis for multifunctional roles of mammalian aminopeptidase N

“…However, an unknown activity of APN independent from its aminopeptidase activity also contributes to tumor migration, as suggested by several other studies: APN-mediated tumor migration can be blocked by antibodies that do not target the aminopeptiase activity of APN, and tumor cells expressing an enzymatically inactive APN also show enhanced migration (16,20). Besides mediating tumor migration, APN also mediates other cell motility processes, such as immune cell chemotaxis and sperm motility (21)(22)(23)(24)(25). Additionally, APN mediates cell-cell adhesion by interacting with other cell-surface proteins (16,(26)(27)(28).…”