Direct biochemical analysis has been applied to bovine testicular anti‐Müllerian hormone (AMH), purified from incubation medium of bovine fetal testes by immunochromatography on a monoclonal antibody. The hormone contains a high proportion of hydrophobic amino acids and 13.5% carbohydrate. The oligosaccharide composition suggests that both N‐ and O‐glycosidically linked chains are present. The molecular extinction coefficient is 3.27 ± 0.06. One RIA unit, defined as the amount of hormone released by 1 g fetal bovine testicular tissue incubated during 4 h, corresponds to 3.06 ± 0.17 /smg protein.

Two lectins, RPA 1 and RPA 3, were purified from Robinia pseudoacacia seeds. These two lectins differ in their physicochemical and biological properties. By analytical ultracentrifugation the Mr values of RPA 1 and RPA 3 were estimated to be 59,000 and 105,000 respectively. From SDS/polyacrylamide-gel-electrophoresis data it was estimated that RPA 1 consisted of two subunits of Mr 34,000, and RPA 3 of two types of subunits (Mr 30,500 and 29,000). RPA 1 and RPA 3 were found to be glycoproteins of comparable amino acid composition. RPA 1 was the more highly glycosylated molecule (11.6% versus 4.3%). The carbohydrate-specificity of RPA 1 appears to be complex. RPA 3 was inhibited by N-acetyl-D-galactosamine and human alpha-glycoproteins. Both lectins exerted a mitogenic effect on human peripheral-blood lymphocytes. Concentrations between 0.5 and 1 microgram of RPA 3/ml gave optimal proliferative responses, whereas for RPA 1 concentrations higher than 10 micrograms/ml were needed for these responses.

Glycoprotein MI12, the major cell surface glycoprotein (molecular mass 11 0 kDa) of Zuj&lu hepatoma ascites cells, contains about 25 0-glycosidic oligosaccharide chains per molecule. They were released as oligosaccharidealditols by alkaline borohydride treatment of MU2, and purified by gel filtration on Bio-Gel P-6 followed by high-voltage paper electrophoresis. Four oligosaccharide-alditol fractions (A -D) were obtained in relative yields of 8 :6: 3 : 3.The structure of the components of fractions A-C was determined by 500-MHz 'H-NMR spectroscopy in combination with sugar composition analysis, to be as follows. Gal~(1+3)[NeuAca(2-r3)Gal~(1+4)GlcNAc~(1+6)]GalNAc-ol (C) NeuAcac(2+3)Gal/?(1+3)GalNAc-olOn the basis of sugar composition and characteristics on Bio-Gel P-6 filtration, paper electrophoresis and thin-layer chromatography, the structure of the carbohydrate component of fraction D is proposed to be as follows.

Expression of the glycoprotein MII2 antigen originally identified in Zajdela ascites hepatoma cells was investigated in several normal rat tissues and in more or less differentiated tumours using biochemical and immunological approaches. SDS-polyacrylamide gel electrophoresis followed by fluorography or immunoblotting with an antiserum raised against the purified MII2 antigen revealed that this antigen was absent from normal liver cells. ELISA assays, indirect immunofluorescence and immunoprecipitation experiments using the same antiserum showed that this glycoprotein was not expressed in various normal tissues such as liver, spleen, lung, pancreas, intestine and stomach, but it was unexpectedly detected in kidney and thymic tissues. However, the molecular weight of the antigens immunoprecipitated from kidney and thymus was lower than the one of MII2 (Mr of 60,000 versus 110,000-160,000 for purified MII2). No staining was observed in embryonic rat liver at 10 and 20 days of development. Moreover, this antigen was present on the surface of Morris hepatoma 7777, another rapidly proliferating and poorly differentiated hepatocellular carcinoma. In contrast, this antigen was not detected on the surface of in vitro Zajdela hepatoma cells (ZHC) or of partially differentiated hepatomas (Faza) which have recovered some hepatic functions. In addition, the MII2 antigen was found on the human non-hepatic HT-29 tumour cell line, under its undifferentiated form (HT-29 G+ subline). The possible relationships between the expression of this antigen and both the malignant transformation process and the differentiation process are discussed.

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