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Molecular characterization of glutamic acid/glutamine-rich secretory proteins from rat submandibular glands 总被引:3,自引:0,他引:3
L Mirels G S Bedi D P Dickinson K W Gross L A Tabak 《The Journal of biological chemistry》1987,262(15):7289-7297
A family of abundant rat submandibular gland secretory proteins has been identified in glandular extracts and characterized. By amino acid analysis these proteins contain approximately 35% glutamic acid and glutamine plus 14% proline. They have therefore been named "Glx-rich proteins" (GRP). Plasmids containing cDNAs for a GRP have been isolated from a cDNA library prepared from rat submandibular gland poly(A)+RNA. The nucleotide sequence of these cDNAs have been determined. Approximately half of the protein coding sequence is composed of a 23-residue tandem repeat which is repeated five times. The first four repeats are highly conserved at both the nucleotide and amino acid level and consist of the prototype sequence: Asn-Gln-Glu-Pro-Pro-Ala-Thr-Ser-Gly-Ser-Glu-Glu-Glu-Gln-Gln-Gln-Gln-Glu- Pro-Thr-Gln-Ala-Glu. The expression of GRP appears to be specific to the submandibular gland. In vitro assays demonstrate that the GRP have a marked affinity for hydroxyapatite. This suggests that GRP may play a role in the formation of the protective acquired pellicle at the saliva-tooth interface. 相似文献
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Andrea Schmidt Stephanie Bringer-Meyer Karl Poralla Hermann Sahm 《Applied microbiology and biotechnology》1989,30(2):170-175
Summary The influence of different primary aliphatic alcohols on the activities of two key enzymes in hopanoid biosynthesis of Zymomonas mobilis was investigated. By use of 14C- and 3H-labelled substrates the enzymes 3-hydroxy-3-methylglutaryl-CoA-reductase and squalene-hopenecyclase were detected with activities of 1.6 pmol x (min x mg protein)-1 and 2.3 pmol x- (min x mg protein)-1, respectively. Cells grown in the presence of 6% (v/v) ethanol did not show higher activities of these enzymes than cells grown in the presence of 1% (v/v) ethanol. Furthermore, 3-hydroxy-3-methylglutaryl-CoA-reductase was not activated by ethanol. However, ethanol activated the squalene-hopene-cyclase when added to the enzyme test system. Besides ethanol, propanol also had a positive effect on the squalene-hopene-cyclase: the enzyme's activity increased 1.7-fold in the presence of either alcohol at a concentration of 6% (v/v). This corresponded with a similar increase of hopanoid content of whole cells when grown in the presence of 6% (v/v) added ethanol or propanol. These results indicated that the squalene-hopene-cyclase has a regulatory function in the alcohol dependent hopanoid biosynthesis of Z. mobilis.Abbreviation HMG-CoA-reductase
3-hydroxy-3-methylglutaryl-coenzyme A-reductase 相似文献