Semenogelins I and II bind zinc and regulate the activity of prostate-specific antigen.

Article Details

Citation

Copy to clipboard

Jonsson M, Linse S, Frohm B, Lundwall A, Malm J

Semenogelins I and II bind zinc and regulate the activity of prostate-specific antigen.

Biochem J. 2005 Apr 15;387(Pt 2):447-53. doi: 10.1042/BJ20041424.

PubMed ID

15563730 [ View in PubMed

]

Abstract

In semen, the gel proteins SgI and SgII (semenogelins I and II) are digested by PSA (prostate-specific antigen), resulting in liquefaction and release of motile spermatozoa. Semen contains a high concentration of Zn2+, which is known to inhibit the protease activity of PSA. We characterized the binding of Zn2+ to SgI and SgII and found evidence that these proteins are involved in regulating the activity of PSA. Intact SgI and SgII and synthetic semenogelin peptides were used in the experiments. Binding of Zn2+ was studied by radioligand blotting, titration with a zinc (II) fluorophore chelator and NMR analysis. A chromogenic substrate was used to measure the enzymatic activity of PSA. SgI and SgII bound Zn2+ with a stoichiometry of at least 10 mol (mol of protein)(-1) and with an average dissociation constant of approx. 5 microM per site. Moreover, Zn2+-inhibited PSA was activated by exposure to SgI or SgII. Since both proteins have high affinity for Zn2+ and are the dominating proteins in semen, they probably represent the major Zn2+ binders in semen, one function of which may be to regulate the activity of PSA. The system is self-regulating, and PSA is maintained in an active state by its substrate.

DrugBank Data that Cites this Article

Drug Targets

Drug	Target	Kind	Organism	Pharmacological Action	Actions
Zinc chloride	Semenogelin-1	Protein	Humans	Unknown	Cofactor	Details
Zinc chloride	Semenogelin-2	Protein	Humans	Unknown	Cofactor	Details
Zinc sulfate, unspecified form	Semenogelin-1	Protein	Humans	Unknown	Cofactor	Details
Zinc sulfate, unspecified form	Semenogelin-2	Protein	Humans	Unknown	Cofactor	Details