Amino acid sequence in the region of the reactive serine residue of eel acetylcholinesterase

Biochemistry ◽  
1973 ◽  
Vol 12 (15) ◽  
pp. 2946-2950 ◽  
Author(s):  
Norwood K. Schaffer ◽  
Harry O. Michel ◽  
Alec F. Bridges
1980 ◽  
Vol 187 (3) ◽  
pp. 863-874 ◽  
Author(s):  
D M Johnson ◽  
J Gagnon ◽  
K B Reid

The serine esterase factor D of the complement system was purified from outdated human plasma with a yield of 20% of the initial haemolytic activity found in serum. This represented an approx. 60 000-fold purification. The final product was homogeneous as judged by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis (with an apparent mol.wt. of 24 000), its migration as a single component in a variety of fractionation procedures based on size and charge, and its N-terminal amino-acid-sequence analysis. The N-terminal amino acid sequence of the first 36 residues of the intact molecule was found to be homologous with the N-terminal amino acid sequences of the catalytic chains of other serine esterases. Factor D showed an especially strong homology (greater than 60% identity) with rat ‘group-specific protease’ [Woodbury, Katunuma, Kobayashi, Titani, & Neurath (1978) Biochemistry 17, 811-819] over the first 16 amino acid residues. This similarity is of interest since it is considered that both enzymes may be synthesized in their active, rather than zymogen, forms. The three major CNBr fragments of factor D, which had apparent mol.wts. of 15 800, 6600 and 1700, were purified and then aligned by N-terminal amino acid sequence analysis and amino acid analysis. By using factor D labelled with di-[1,3-14C]isopropylphosphofluoridate it was shown that the CNBr fragment of apparent mol.wt. 6600, which is located in the C-terminal region of factor D, contained the active serine residue. The amino acid sequence around this residue was determined.


1960 ◽  
Vol 77 (1) ◽  
pp. 149-163 ◽  
Author(s):  
M. A. Naughton ◽  
F. Sanger ◽  
B. S. Hartley ◽  
D. C. Shaw

1972 ◽  
Vol 50 (1) ◽  
pp. 63-90 ◽  
Author(s):  
K. G. Welinder ◽  
L. B. Smillie

Horseradish peroxidase (HRP) was digested with thermolysin. On fractionation on Sephadex G-25, Fine Chromobeads type P (Dowex 50 type resin) and by high-voltage paper electrophoresis, we isolated about 120 thermolytic peptides. Some experimentation on the composition of the pyridine acetate gradient, used for elution of the cation exchanger, is reported. All peptides were characterized with respect to amino acid composition, N-terminal residue, and pH 6.5 mobility. Unknown peptides or peptides not corresponding unambiguously to previously established tryptic sequences were subjected to dansyl-Edman analysis. Thermolytic peptides accounting for all tryptic sequences except a dipeptide and a tripeptide, and unique thermolytic sequences accounting for about 100 amino acid residues, were obtained. Nine convincing and several indicative overlaps were established for known tryptic sequences. The sequences around all four disulfide bridges, the three histidine residues, and the only tryptophan residue have been elucidated. Eight sites of carbohydrate attachment have been identified. For seven of these sites we have evidence for attachment to asparagine, and for six of the sites the carbohydrate-bound asparagine was found in the well-known sequences Asn–X–Ser/Thr. The remaining two sequences, though incomplete, are compatible with this pattern. Tentatively we suggest a pyrrolidone carboxyl N-terminal for HRP. The specificity of trypsin implicates a sequence found in two varieties, differing only by a C-terminal serine residue at the C-terminus of HRP. A discussion of the possible complications of the acidic heme extraction on the results obtained is included.


1981 ◽  
Vol 46 (3) ◽  
pp. 626-639
Author(s):  
Ladislav Morávek

By the analyses of chymotryptic, and thermolytic peptides the amino acid sequence was determined of cyanogen bromide fragment CB4 representing the region of the pepsin chain between the N-terminus and methonine-residue I: Ile-Gly-Asp-Glu-Pro-Leu-Glu-Asn-Tyr-Leu-Asp-Thr-Glu-Tyr-Phe-Gly-Thr-Ile-Gly-Ile-Gly-Thr-Pro-Ala-Gln-Asp-Phe-Thr-Val-Ile-Phe-Asp-Thr-Gly-Ser-Ser-Asn-Leu-Trp-Val-Pro-Ser-Val-Tyr-Cys-Ser-Ser-Leu-Ala-Cys-Ser-Asp-His-Asn- + Gln-Phe-Asn-Pro-Asp-Asp-Ser-Ser-Thr-Phe-Glu-Ala-Thr-Ser-Gln-Glu-Leu-Ser-Ile-Thr-Tyr-Gly- + Thr-Gly-Ser-Met. The serine residue (Ser) in position 68 of pepsin is phosphorylated. By sequential analysis of chymotryptic, tryptic, and thermolytic peptides the amino acid sequence was determined of cyanogen bromide fragment CB6 representing the region between methionine residues II and III in the pepsin chain: Asp-Gly-Glu-Thr-Ile-Ala-Cys-Ser-Gly-Gly-Cys-Gln-Ala- + Ile-Val-Asp-Thr-Gly-Thr-Ser-Leu-Leu-Thr-Gly-Pro-Thr-Ser-Ala-Ile-Ala-Asn-Ile-Gln-Ser-Asp- + Ile-Gly-Ala-Ser-Glu-Asn-Ser-Asp-Gly-Glu-Met. The aspartic acid residue (Asp) in position 16 of this fragment is identical with the residue reacting with diazo inhibitors which forms a part of the active center of the enzyme. Both half-cystine residues of fragment CB4 and fragment CB6 are linked to one another by a disulfide bond in native pepsin.


1990 ◽  
Vol 269 (2) ◽  
pp. 535-537 ◽  
Author(s):  
C J Bailey ◽  
T P Smith

Comparison of amino acid sequence data suggested that there may be a functional relationship between the staphylococcal epidermolytic toxins and V8 proteinase. The hypothesis was tested by treating epidermolytic toxin with di-isopropyl phosphorofluoridate, which bound specifically at serine-195, the homologue of the active-site serine residue of V8 proteinase.


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