| 1. |
- Abrahamson, Magnus, et al.
(författare)
-
Structure and expression of the human cystatin C gene
- 1990
-
Ingår i: Biochemical Journal. - 1470-8728. ; 268:2, s. 287-294
-
Tidskriftsartikel (refereegranskat)abstract
- The structural organization of the gene for the human cysteine-proteinase inhibitor cystatin C was studied. Restriction-endonuclease digests of human genomic DNA hybridized with human cystatin C cDNA and genomic probes produced patterns consistent with a single cystatin C gene and, also, the presence of six closely related sequences in the human genome. A 30 kb restriction map covering the genomic region of the cystatin C gene was constructed. The positions of three polymorphic restriction sites, found at examination of digests of genomic DNA from 79 subjects, were localized in the flanking regions of the gene. The gene was cloned and the nucleotide sequence of a 7.3 kb genomic segment was determined, containing the three exons of the cystatin C structural gene as well as 1.0 kb of 5'-flanking and 2.0 kb of 3'-flanking sequences. Northern-blot experiments revealed that the cystatin C gene is expressed in every human tissue examined, including kidney, liver, pancreas, intestine, stomach, antrum, lung and placenta. The highest cystatin C expression was seen in seminal vesicles. The apparently non-tissue-specific expression of this cysteine-proteinase inhibitor gene is discussed with respect to the structure of its 5'-flanking region, which shares several features with those of housekeeping genes.
|
|
| 3. |
- Jonsson, Magnus, et al.
(författare)
-
Semenogelins I and II bind zinc and regulate the activity of prostate-specific antigen
- 2005
-
Ingår i: Biochemical Journal. - 0264-6021. ; 387:Part 2, s. 447-453
-
Tidskriftsartikel (refereegranskat)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 cool (mol of protein)(-1) and with an average dissociation constant of approx. 5 mu M 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.
|
|
