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Ecto‐diadenosine polyphosphates hydrolase activity on human prostasomes
Author(s) -
Minelli Alba,
Allegrucci Cinzia,
Liguori Lavinia,
Ronquist Gunnar
Publication year - 2002
Publication title -
the prostate
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.295
H-Index - 123
eISSN - 1097-0045
pISSN - 0270-4137
DOI - 10.1002/pros.10062
Subject(s) - hydrolase , enzyme , biochemistry , chemistry , hydrolysis , adenosine , biology
BACKGROUND Ecto‐diadenosine polyphosphates are ubiquitous compounds with several physiological roles. Ecto‐diadenosine polyphosphates hydrolase control their actions by degrading and terminating their signaling. The present work deals with the identification and partial characterization of ecto‐diadenosine polyphosphates hydrolase on human prostasomes. METHODS Reverse‐phase and paired‐ion HPLC techniques have been used. RESULTS Prostasomes have an ecto‐diadenosine polyphosphates hydrolase that leads to the degradation of several diadenosine compounds. Kinetic parameters of the enzyme show that diadenosine tetraphosphate is the preferred substrate that is further metabolized by the prostasome‐ecto‐nucleotidases to adenosine. The ecto‐enzyme is bound to the prostasome‐membranes through a GPI‐anchor and is activated by physiological concentration of Ca +2 , Mg +2 , and Mn +2 . Its optimum pH is also in the slightly alkaline physiological range. Human spermatozoa do not possess this hydrolytic activity, but they can acquire it after fusion with prostasomes. CONCLUSIONS The existence of an enzyme capable of degrading diadenosine compounds and can be transferred to human spermatozoa suggests new physiological implications for the role of prostasomes in fertilization. Prostate 51: 1–9, 2002. © 2002 Wiley‐Liss, Inc.