Publication Date:
1988-11-11
Description:
The glycoprotein hormones lutropin (LH) and follitropin (FSH), which have common alpha-subunits but hormone-specific beta-subunits, are both synthesized in the gonadotroph. However, they bear Asn-linked oligosaccharides that differ in structure. Those on LH terminate with the sequence SO4-4GalNAc beta 1----4GlcNAc beta 1----2Man alpha, whereas those on FSH terminate with the sequence sialic acid alpha-Gal beta 1----4GlcNAc beta 1----2Man alpha. A GalNAc-transferase was identified in bovine pituitary membranes that recognizes features of the alpha-subunit peptide and adds GalNAc to its oligosaccharides with an apparent Michaelis constant of 25 micromolar. The different patterns of glycosylation for LH and FSH indicate that access to the protein recognition marker on the alpha-subunit is modulated by the associated beta-subunit. The tightly regulated synthesis of sulfated and sialylated oligosaccharides on the pituitary glycoprotein hormones suggests these oligosaccharides have an important biological role.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Smith, P L -- Baenziger, J U -- HD-20197/HD/NICHD NIH HHS/ -- R37-CA21923/CA/NCI NIH HHS/ -- T32-ES07066/ES/NIEHS NIH HHS/ -- New York, N.Y. -- Science. 1988 Nov 11;242(4880):930-3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Pathology, Washington University School of Medicine, St. Louis, MO 63110.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2460923" target="_blank"〉PubMed〈/a〉
Keywords:
Acetylgalactosamine/metabolism
;
Animals
;
Carbohydrate Sequence
;
Cattle
;
Cell Membrane/enzymology
;
Follicle Stimulating Hormone/*biosynthesis/metabolism
;
Follicle Stimulating Hormone, beta Subunit
;
Galactosyltransferases/*metabolism
;
Glycoprotein Hormones, alpha Subunit/metabolism
;
Glycosylation
;
Humans
;
Luteinizing Hormone/*biosynthesis/metabolism
;
Molecular Sequence Data
;
*N-Acetylgalactosaminyltransferases
;
Oligosaccharides/metabolism
;
Pituitary Gland/*enzymology
;
Placenta/enzymology
;
Sulfates/metabolism
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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