Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.1 (chymotrypsin)
 10,938 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The chemical structure of carcinoembryonic antigen (CEA) and two closely related antigens, normal fecal antigen-2 (NFA-2) in normal adult feces and nonspecific cross-reacting antigen-2 (NCA-2) in the meconium, were further analyzed comparatively. The NH2-terminal amino acid sequence of NCA-2 was newly determined to position 18 and found to be identical to that so far determined for CEA- and NFA-2. After proteolytic digestion with chymotrypsin or protease V8, the digests of these antigens showed two groups of fragments upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis. One consisted of the sharply banded fragments which were identical in all antigens and stained only with Coomassie brilliant blue (CBB) (five bands in the range 2500-10,000 daltons for chymotrypsin and 11 bands in the range 8000-35,000 daltons for protease V8, respectively), and the other consisted of the dispersed fragments which had variable mol. wts in the range 10,000-100,000 and were stainable with both CBB and periodic acid-Schiff reagent. Elution profiles of CEA, NFA-2, and NCA-2 from lectin columns, especially from concanavalin A-Sepharose columns, suggested some differences in oligosaccharide chains between them. These results indicate that the fundamental chemical structure of these antigens seems to be very similar to one another and is divided into two parts; an homologous portion(s) which is common to all three antigens and contains no sialylated sugar components, and a heterogeneous portion(s) which is variable among these antigens and contains sialylated sugar components.
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PMID:Further comparative studies on chemical properties of carcinoembryonic antigen in tumor tissues and closely related antigens in adult feces and meconium. 388 29

The immunologic reactivity of glycoprotein antigens extractable from individual, histologically different ovarian and uterine cancers was studied taking into account their relationship with carcinoembryonic antigen (CEA), nonspecific cross-reacting antigen (NCA), alpha-feto-protein (AFP), and alpha-1-antichymotrypsin. All studies were performed using specific immune sera against perchloric acid (PCA) extracts of ovarian mucinous cystadenocarcinoma (anti-PCA-CaOm) and cervical squamous cell carcinoma (anti-PCA-CaCx), and antisera against the reference antigens mentioned above. A considerable antigenic heterogeneity and the existence of several immunologically related antigenic systems were found: 1) CEA-like antigens; 2) NCA-type antigens; 3) an antigen different from CEA and NCA present in ovarian mucinous adenocarcinomas and often cross-reacting, but not identical with respective antigens of uterine body and cervical carcinomas; 4) an antigen reacting with anti-alpha-1-anti-chymotrypsin serum; and 5) an antigen reacting with anti-AFP serum.
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PMID:Tumor-associated antigens in female genital tract cancers. 620 30