Polyamide layer chromatography of DNP-amino acids

The partial amino acid sequence of the extracellular beta-lactamase I of Bacillus cereus 569/H

The chemical structure of the extracellular beta-lactamase I of Bacillus cereus 569/H was investigated. Three electrophoretically homogenous charge variants of this enzyme were isolated and amino acid analysis of each revealed no significant differences. However, a degree of N-terminal heterogeneity was found by direct end-group modification of the protein and also on alignment of peptides from tryptic and chymotryptic digestion. The N-terminal heterogeneity observed was great enough to explain the production of the beta-lactamase I isoenzymes which are probably produced by postsynthesis modification of a single gene product. Over 80% of the amino acid sequence of beta-lactamase I was determined by the detailed analysis of peptides derived from tryptic, chymotryptic and thermolytic digests. Five polypeptide fragments were constructed from these data and aligned by comparison with the known amino acid sequences of the penicillinases produced by Bacillus licheniformis and Staphylococcus aureus (Ambler & Meadway, 1969). About 60% of the proposed sequence was identical with that of B. licheniformis penicillinase, whereas the S. aureus enzyme had only about 40% of its residues in common with beta-lactamase I. These results are discussed with reference to the possible evolutionary relationships existing between known beta-lactamases. Detailed evidence for the amino acid sequence proposed has been deposited as Supplementary Publication SUP 50044 (27 pages) at the British Library (Lending Division), Boston Spa, Wetherby, W. Yorks. LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1975), 145, 5.

Experimental studies on the bridging hypothesis of anaphylaxis: haptenic determinants required to elicit immediate-type reactions in calf skin by separate or concurrent sensitization with reagins of different specificity

The present study has established, that cows suitably immunized with either DNP-edestin (DNP-Ed), di-DNP-gramicidin-J [(DNP)(2)-Gram], respectively, or p-azobenzenearsonate-Ed (ABA-Ed) synthesized and secreted reaginic antibodies (IgE) into colostrum. Whereas ABA-Ed failed to elicit more than a low response, there was however a persistent and increased antibody synthesis between 10 and 56 days after priming with DNP-Ed. Bivalent and multivalent DNP haptens differing in molecular size, degree of substitution, and rigidity were compared for their effectiveness in eliciting Prausnitz-Küstner (P-K) reactions in either newborn colostrum-deprived calves or in those 4 wk of age. The sensitization with reaginic anti-DNP antibody has been accomplished either by feeding colostrum of the immunized dam or by intradermal injection of reaginic serum or colostral whey. It could be demonstrated that equimolar doses of the bivalent alpha,N-(epsilon,N-DNP-aminocaproyl-)-epsilon,N-DNP-L-lysine and the multivalent dinitrophenylated bovine serum albumin were equally effective in eliciting reactions in skin sites provided that a high affinity antibody was used for sensitization. By contrast, the comparatively rigid, bivalent hapten, (DNP)(2)-Gram consistently failed to induce comparable reactions. Furthermore, it was clearly shown that optimal distances of determinant groups on the haptenic molecule are a prerequisite for positive P-K reactions, since alpha,epsilon,N-bis-DNP-lysine failed to induce comparable reactions. Concurrent sensitization of skin sites with reaginic anti-DNP and anti-ABA antibodies provides the final proof that cross-linking of two adjacent reaginic molecules on the mast cell surface by a bivalent hapten is required for effective elicitation of immediate-type reactions. This has been accomplished by utilizing the bivalent epsilon,N-DNP-alpha,N-[(4-hydroxy-3-azobenzenearsonic acid)-phenacetyl]-L-lysine (DNP-ABA) carrying noncross-reactive haptenic groups, which was consistently effective in eliciting P-K reactions in doubly but never in singly sensitized skin sites. It is apparent from the results that equimolar doses of monovalent haptens could completely inhibit the response to DNP-ABA. The present studies finally establish that mast cells of newborn colostrum-deprived calves lack IgE molecules on their surface. Thus, mast cells of newborn calves may be unique, to investigate the molecular mechanisms involved in immediate-type reactions more precisely.