Galanin — a novel biologically active peptide from porcine intestineThe isolation of a novel biologically active peptide, designated galanin, is described. The peptide was discovered by the detection of its C-terminal amide structure in porcine intestinal extract using a chemical method. It was found that galanin consists of 29 amino acids and the complete amino acid sequence is: Gly-Trp-Thr-Leu-Asn-Ser-Ala-Gly-Tyr-Leu-Leu-Gly-Pro-His-Ala-Ile-Asp-Asn-His -Arg-Ser -Phe-His-Asp-Lys-Tyr-Gly-Leu-Ala-NH2. Galanin was found to contract smooth muscle preparations from the rat and to cause a mild and sustained hyperglycemia in dog.
Identification of three classes of cytosolic glutathione transferase common to several mammalian species: correlation between structural data and enzymatic properties.Bengt Mannervik, Per Ålin, Claes Guthenberg et al.|Proceedings of the National Academy of Sciences|1985 The major isoenzymes of cytosolic glutathione transferase (EC 2.5.1.18) from rat, mouse, and man are shown to share structural and catalytic properties that can be used for species-independent classification. Rat, mouse, and human isoenzymes were grouped with respect to amino-terminal amino acid sequences, after correlation of seven structures analyzed in the present investigation with structures determined earlier. The isoenzymes were also characterized by substrate specificities and sensitivities to inhibitors, and the data were subjected to pattern recognition analysis. In addition, the various isoenzymes were tested for cross-reactivity by immunoprecipitation with antibodies raised against rat and human transferases. The different types of data were clearly correlated and afforded an unambiguous division of the isoenzymes into three classes named alpha, mu, and pi. Each of the three mammalian species studied contains at least one isoenzyme of each class. It is suggested that the similarities of the isoenzymes in a class reflect evolutionary relationships and that the classification applies generally.
The human antimicrobial and chemotactic peptides LL-37 and α-defensins are expressed by specific lymphocyte and monocyte populationsWe identified antibacterial components in human T and natural killer (NK) cells by using freshly isolated lymphocytes enriched for T and NK cells as starting material. After growing these lymphocytes for 5 days in the presence of interleukin (IL)-2, we isolated and characterized several antibacterial peptides/proteins from the supernatant-alpha-defensins (HNP 1-3), LL-37, lysozyme, and a fragment of histone H2B-although other active components were also present. We then used reverse transcriptase-polymerase chain reaction to search for expression of the gene coding for LL-37 in several B-cell lines, gammadelta T-cell lines, NK clones, and one monocytic cell line, with positive results, but found no expression in several alphabeta T-cell lines. The alpha-defensins (HNP 1-3) were also found to be expressed in several of these cell lines. To confirm the presence of these antibacterial peptides in lymphocytes, we localized them to NK, gammadelta T cells, B cells, and monocytes/macrophages by using double-staining immunohistochemical analysis of freshly isolated lymphocytes. We also found that primary cultures of lymphocytes transcribe and secrete LL-37 and that these processes are affected by IL-6 and interferon-gamma. In addition, we demonstrated that LL-37 has chemotactic activity for polymorphonuclear leukocytes and CD4 T lymphocytes, whereas others have shown chemotactic activity for human alpha-defensins (HNP 1-2). These findings suggest that microbicidal peptides are effector molecules of lymphocytes and that antibacterial activity previously shown to be derived from T and NK cells may be partly mediated by the antibacterial peptides LL-37 and HNP 1-3.