Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.6.4 (chondroitinase)
 2,039 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The murine monoclonal antibody (MAb) designated DF3 has defined a high m.w. antigen detectable in human breast carcinomas and in human milk. DF3 antigen is detectable on apical borders of secretory mammary epithelial cells and in the cytosol of less differentiated malignant cells. DF3 antigen expression has been shown to correlate with the degree of human breast tumor differentiation, and the detection of a cross-reactive species in human milk has suggested that DF3 antigen might be useful as a biochemical marker of differentiated mammary epithelial cells. To further characterize DF3 antigen, we have developed an approach to purify the cross-reactive species by using gel filtration and antibody affinity chromatography. The affinity column-purified DF3 antigen was absorbed by wheat germ agglutinin and peanut agglutinin, but not by concanavalin A or lentil lectin. In contrast, wheat germ agglutinin inhibited MAb DF3 reactivity with the purified antigen, whereas there was little, if any, inhibition when using peanut agglutinin. These findings are thus consistent with the involvement of terminal N-acetyl-D-neuraminic acid and/or N-acetylglucosamine residues in the antigenic site. DF3 antigenicity was also sensitive to neuraminidase, but not chondroitinase ABC, chondroitinase AC, chondroitin-4-sulfatase, or hyaluronidase. Furthermore, DF3 antigen was sensitive to Pronase, subtilisin BPN', and alpha-chymotrypsin. The presence of O-glycosidic linkages between carbohydrate and protein in the DF3 antigenic site was further supported by the presence of NaBH4-sensitive sites. Together, these results suggest that sialyl oligosaccharides present on a peptide backbone are required for maintaining DF3 antigenicity. Similar findings have been demonstrated for DF3 antigen purified from both human milk and breast cancer effusions. However, the DF3 antigen in human milk consisted of a single high m.w. species, whereas the tumor-associated antigen consisted of two distinct glycoproteins with m.w. of 330,000 and 450,000. These findings may be relevant to the recent demonstration that distinct high m.w. DF3 antigens are elevated in the circulation of patients with breast carcinoma.
 ...
PMID:Purification and characterization of a high molecular weight glycoprotein detectable in human milk and breast carcinomas. 404 99

Certain constitutive skin basement membrane components, such as bullous pemphigoid antigens and epidermolysis bullosa acquisita antigen, were discovered because they were targeted by an autoimmune reaction. We aimed to purify and characterize a 105-kDa skin basement membrane protein termed p105 recognized by autoantibodies (anti-p105) from patients with a unique immune-mediated subepidermal blistering skin disease. A simian virus 40-transformed human fibroblast cell line that synthesizes and secretes p105 was utilized as the protein source. p105 was partially purified by salt-gradient fractionation of serum-free conditioned medium through a Mono Q anion-exchange column and by examining each fraction with protein staining and immunoblotting against anti-p105. p105 was isolated from polyacrylamide gel electrophoresis gels, blotted onto polyvinylidene difluoride membrane, and subjected to protein microsequencing. The 20 microsequenced N-terminal amino acids exhibited no homology to known basement membrane proteins but exhibited a 70% homology to a 90-kDa tumor-associated antigen. Antibodies raised against a peptide generated from these amino acid sequences reacted to a 105-kDa western-blotted keratinocyte and fibroblast protein and a basement membrane component. p105 resisted digestion by glycosidases chondroitinase ABC, neuraminidase, and N-glycosidase F but was cleaved by protease V8 to antigenic fragments of 22 kDa and 14 kDa. The synthesis of p105 was inhibited by cycloheximide. We conclude that p105 is a unique basement membrane component produced by both keratinocytes and fibroblasts.
 ...
PMID:The 105-kDa basement membrane autoantigen p105 is N-terminally homologous to a tumor-associated antigen. 875 64