Browsing by Subject "Ovary"

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    Identification of N -Linked Glycosylation Sites in Human Testis Angiotensin-converting Enzyme and Expression of an Active Deglycosylated Form
    (1997) Yu, X Christopher; Sturrock, Edward D; Wu, Zhuchun; Biemann, Klaus; EHLERS, Mario R W; Riordan, James F
    The sites of glycosylation of Chinese hamster ovary cell expressed testicular angiotensin-converting enzyme (tACE) have been determined by matrix-assisted laser desorption ionization/time of flight/mass spectrometry of peptides generated by proteolytic and cyanogen bromide digestion. Two of the seven potential N-linked glycosylation sites, Asn90 and Asn109, were found to be fully glycosylated by analysis of peptides before and after treatment with a series of glycosidases and with endoproteinase Asp-N. The mass spectra of the glycopeptides exhibit characteristic clusters of peaks which indicate the N-linked glycans in tACE to be mostly of the biantennary, fucosylated complex type. This structural information was used to demonstrate that three other sites, Asn155, Asn337, and Asn586, are partially glycosylated, whereas Asn72 appears to be fully glycosylated. The only potential site that was not modified is Asn620. Sequence analysis of tryptic peptides obtained from somatic ACE (human kidney) identified six glycosylated and one unglycosylated Asn. Only one of these glycosylation sites had a counterpart in tACE. Comparison of the two proteins reveals a pattern in which amino-terminal N-linked sites are preferred. The functional significance of glycosylation was examined with a tACE mutant lacking the O-glycan-rich first amino-terminal 36 residues and truncated at Ser625. When expressed in the presence of the alpha-glucosidase I inhibitor N-butyldeoxynojirimycin and treated with endoglycosidase H to remove all but the terminal N-acetylglucosamine residues, it retained full enzymatic activity, was electrophoretically homogeneous, and is a good candidate for crystallographic studies.
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    Multilocal expression of B-type allatostatins in crickets (Gryllus bimaculatus)
    (2004) Wang, Junling; Meyering-Vos, Martina; Hoffmann, Klaus H
    B-type allatostatins (AST) inhibit the biosynthesis of juvenile hormone (JH) in vitro in crickets, but are also present in other insects, where they may bare different functions. By means of one-step RT-PCR and in situ hybridization recently, we could show that the mRNA of the gene is expressed in various cells of the central nervous system, but also in endocrine cells of the gut. The latter results corroborated a function of these peptides in regulating gut motility. Here we report on the expression of the gene in the ovary, the fat body and the flight muscles of female adult crickets, which suggests further putative functions of the B-type allatostatins beyond their role as brain–gut peptides.