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The human blood group A-specified 3-ar-N-acetylD-galactosaminyl-, B-specified 3iu-D-galactosyl- and H-specified 2-o-L-fucosyltransferases occur in soluble form in sera [l-6] and as membrane-bound enzymes in erythrocytes [I ,7-lo] from individuals with common ABO phenotypes. They are associated with two different genetic systems: the first two are related to the ABO locus and the third to the Hh locus. These activities have been also studied in unusual blood groups such as ‘Bombay’ phenotypes [7,8,11 ,121, A variants [9,13], B variants: B weak [14]; B, [ 10,14,15]; and cisAB [ 16-181. In this work, B variants from Ba, B, and Be, subgroups [ 191 were investigated for A, B and H blood group glycosyltransferase activities using low molecular weight acceptors or (and) 0 red cell conversion. Studies on N-acetylglucosamine$-D-galactosyItransferase activity in the sera were included as controls of state of preservation. Moreover, when activities were not detected, attempts were made to concentrate potential weak B-transferase.

A radio-ribonuclease inhibitor assay based on the interaction of 125I-angiogenin with ribonuclease inhibitor (RI) was used to detect pancreatic-type ribonucleases and potential modulators of their action. We show that highly basic proteins including the homopolypeptides poly-arginine, poly-lysine and poly-ornithine, core histones, spermatid-specific S1 protein and the protamines HP3 and Z3 were strong inhibitors of angiogenin binding to RI. A minimum size of poly-arginine and poly-lysine was required for efficient inhibition. The inhibition likely resulted from direct association of the basic proteins with the acidic inhibitor, as RI bound to poly-lysine and protamines while 125I-angiogenin did not. Antagonists of the angiogenin-RI interaction are potential regulators of either angiogenin-triggered angiogenesis and/or intracellular RI function, depending on their preferential target.