Human prothymosin alpha: amino acid sequence and immunologic properties

Prothymosin alpha has been purified from human thymus and its amino acid sequence determined, except for a 15 amino acid segment including 10 glutamyl residues near the middle of the molecule. Like prothymosin alpha from rat thymus [A. A. Haritos, R. Blacher, S. Stein, J. Caldarella, and B. L. Horecker (1985) Proc. Natl. Acad. Sci. USA 82, 343-346], human prothymosin contains the thymosin alpha 1 sequence at its NH2-terminus. It contains a total of 109-110 residues compared to 111-112 for rat prothymosin alpha, with deletions corresponding to positions Gln39 and Lys108 of the rat polypeptide. Human prothymosin alpha also differs from rat prothymosin alpha at positions corresponding to residues 87, 92, and 102 of the latter, with substitutions of alanine for proline, alanine for valine, and aspartic acid for glutamic acid, respectively. Human prothymosin is significantly less active than rat prothymosin in protecting mice against infection with Candida albicans and in stimulating release in vivo of migration inhibitory factor. Thus, the differences in amino acid sequences, present mainly the COOH-terminal half of the polypeptides, may determine species specificity in biological properties.     

The complete amino acid sequence of bovine milk angiogenin

The amino acid sequence of angiogenin isolated from bovine milk was deduced by gas-phase sequencing of the protein and its fragments. The protein contains 125 residues and has a calculated molecular mass of 14,577 Da. The sequence is highly homologous (65% identity) to the sequence of human angiogenin, most of the differences being the result of conservative replacements. Like human angiogenin, the bovine protein is also homologous to bovine pancreatic RNase A (34% identity) and the three major active site residues known to be involved in the catalytic process, His-14, Lys-41 and His-115, are conserved. When tested against conventional substrates for RNase A activity, bovine angiogenin displays the same selective ribonucleolytic activity as human angiogenin. The sequence of bovine angiogenin contains the cell recognition tripeptide Arg-Gly-Asp which is not present in the human protein.     

The complete amino acid sequence of bovine skeletal muscle acylphosphatase

The primary structure of bovine skeletal muscle acylphosphatase was determined by performing the sequence analyses of the complete series of tryptic peptides. The amino acid composition of the entire series of peptic peptides was used to reconstruct the sequence by the overlapping method. The proposed structure is further confirmed by analogy with known amino acid sequences of acylphosphatase from skeletal muscle of other vertebrate species. The length of the polypeptide chain is 98 residues, identical to the length of the enzymes from other known mammalian species, but different from that found in turkey. The enzyme is NH2-acetylated and a comparison with the analogous molecular forms from other vertebrate species indicates that there are several long polypeptide stretches strictly conserved (93-97% identical position among mammals, and about 80% between calf and turkey enzymes).     

Primary amino acid sequence of bovine dopamine beta-hydroxylase

Fifty-eight tryptic and Staphylococcus aureus V8 protease generated peptides from bovine dopamine beta-hydroxylase were isolated by reverse-phase high pressure liquid chromatography and sequenced. These peptide sequences were compared with the deduced amino acid sequences of bovine and human dopamine beta-hydroxylase obtained from the cloned cDNAs. Bovine peptide sequences had five differences with the sequence derived from the bovine cDNA, and four of the changes could be accounted for by a single base change in the DNA. N-terminal sequence analysis of the bovine enzyme indicated that it contained two N termini, one of which is 3 amino acids longer than the other and begins with the sequence Ser-Ala-Pro. The amino acid sequences deduced from the bovine and human cDNAs are 19 and 25 amino acids longer, respectively, and these additional amino acids represent leader peptide sequences. Two bovine peptide sequences contained glycosylation sites and gave positive tests for carbohydrate residues, and two others contained the consensus sequence for a glycosylation site but were negative in the carbohydrate test. The bovine enzyme contains 6 Trp, as compared with 7 in the bovine cDNA and 8 in the human cDNA. The protein and bovine cDNA contain 24 Tyr each, as compared with 26 in the human cDNA. These numbers indicate that the true epsilon 1% 280 = 8.95, and, therefore, that it is 28% lower than the previously determined value. The data also identify 5 His-containing regions that may be involved in Cu2+ coordination at the active site.     

The complete amino acid sequence of bovine liver catalase and the partial sequence of bovine erythrocyte catalase

The data upon which the sequence of the 506 residues in the subunit of bovine liver catalase (BLC) is based are presented in detail. A partial sequence of bovine erythrocyte catalase (BEC) which accounts for 493 residues shows complete concordance with the BLC data. On the other hand, BEC has at least 517 residues, that is, an extension beyond the C terminus of the BLC data. Although normally BLC has only 506 residues, there is evidence that, at some point in its history, it also had the C-terminal extension. It is speculated that this extension is lost in BLC either through a different processing of the molecule in liver than in erythrocytes or by partial degradation in the first stages of catabolism.     

The complete amino acid sequence of bovine antithrombin (ATIII)

Bovine antithrombin (ATIII) is a glycoprotein of M_r 56,600. Its primary structure was established using peptide sequences from five different digests. Bovine ATIII exhibits four glycosylation sites as well as human ATIII. The primary structures of bovine and human ATIII were compared: all the residues required for the integrity of the heparin-binding domain are strictly conserved. However, there are differences in the secondary structures of both proteins, bovine and human ATIII.     

The amino acid sequence of the rabbit glycoprotein hormone alpha subunit

The amino acid sequence of the alpha subunit of rabbit (lagomorph) lutropin (lLH) has been determined. Overlapping peptides from trypsin and chymotrypsin digestions were isolated by reverse-phase high-pressure liquid chromatography (HPLC). Sequencing was by the dansyl-Edman procedure. Amide placements were established by HPLC analysis of the PTH amino acid derivatives. The proposed sequence of lLH alpha subunit is (asterisks denote carbohydrate attachment sites): This proposed sequence is highly homologous with the porcine, murine, ovine, and bovine glycoprotein hormone alpha subunit sequences. Two unusual proteolytic cleavages were observed: (1) a cleavage by trypsin between Asn-77 and Ala-78, and (2) a cleavage by chymotrypsin between Ala-45 and Arg-46. Similar enzymatic cleavages were previously reported for equine chorionic gonadotropin alpha subunit by Wardet al. and for these sites in the ovine LH alpha subunit by Liuet al. Chymotrypsin cleaved on the carboxyl side of methionine sulfone residues at positions 51 and 75.     

Cellular distribution of prothymosin alpha and parathymosin in rat thymus and spleen

By means of immunohistochemical methods, we have investigated the cellular distribution of prothymosin alpha and parathymosin in rat thymus and spleen, using specific antibodies raised against thymosin alpha-1 and against parathymosin. We observed prothymosin alpha immunoreactivity in lymphoid cells both in thymus and spleen. In the thymus, prothymosin alpha staining was more marked in cortex than in medulla. In the spleen, prothymosin alpha was found in lymphocytes of the periarteriolar lymphatic sheaths and was especially prominent in the germinal centers. Parathymosin immunoreactivity in the thymus was mainly localized in the medulla; positive cells were reticuloepithelial cells from the thymic reticulum and the blood barrier. Thymocytes were negative. In spleen, parathymosin was found in reticular cells arranged in a ring between the periarteriolar lymphatic sheath and the marginal zone. Our results do not support an exclusive role for these peptides as immune system hormones or cytokines.     

Complete amino acid sequence of human alpha 1-microglobulin

Complete amino acid sequence of human α₁-microglobulin has been established. It is composed of 167 amino acid residues and contains three carbohydrate attachment sites. No amino acid sequence heterogeneity was found.     

The amino acid sequence of the activation peptide of bovine pro-carboxypeptidase A

The amino acid sequence of the activation peptide of bovine pro-carboxypeptidase A subunit I has been determined by automated Edman degradation of the cyanogen bromide fractions derived from the precursor protein. The activation peptide contains 94 amino acid residues in a unique sequence which precedes directly the amino-terminal alanine residue of carboxypeptidase A alpha. A notable feature of the activation peptide is the presence of acidic amino acid residues immediately preceding the site of activation. The amino acid sequence of the activation peptide of bovine pro-carboxypeptidase A shows extensive similarity to those of the corresponding porcine and rat enzymes.