{"id":3104,"date":"2026-10-04T13:31:25","date_gmt":"2026-10-04T13:31:25","guid":{"rendered":"https:\/\/nhdbio.com\/?p=3104"},"modified":"2026-10-04T15:11:42","modified_gmt":"2026-10-04T15:11:42","slug":"%d8%b1%d8%a7%d8%a8%d8%b7%d8%a9-%d8%ab%d9%86%d8%a7%d8%a6%d9%8a-%d8%a7%d9%84%d9%83%d8%a8%d8%b1%d9%8a%d8%aa%d9%8a%d8%af-%d9%81%d9%8a-%d8%a7%d9%84%d8%a8%d8%a8%d8%aa%d9%8a%d8%af-%d9%81%d8%b1%d9%82-%d9%83","status":"publish","type":"post","link":"https:\/\/nhdbio.com\/ar\/peptide-disulfide-bond-two-hydrogen-mass-difference\/","title":{"rendered":"\u062a\u063a\u064a\u0651\u0631 \u0631\u0627\u0628\u0637\u0629 \u062b\u0646\u0627\u0626\u064a \u0627\u0644\u0643\u0628\u0631\u064a\u062a \u0643\u062a\u0644\u0629 \u0627\u0644\u0628\u0628\u062a\u064a\u062f \u0628\u0646\u062d\u0648 2 Da. \u0644\u0645\u0627\u0630\u0627\u061f"},"content":{"rendered":"<p>\u064a\u0645\u0643\u0646 \u0623\u0646 \u064a\u0643\u0648\u0646 \u0644\u0646\u0633\u062e\u062a\u064a\u0646 \u0645\u0646 \u0627\u0644\u0628\u0628\u062a\u064a\u062f \u0646\u0641\u0633 \u062a\u0633\u0644\u0633\u0644 \u0627\u0644\u0623\u062d\u0645\u0627\u0636 \u0627\u0644\u0623\u0645\u064a\u0646\u064a\u0629 \u0644\u0643\u0646 \u0643\u062a\u0644\u062a\u0647\u0645\u0627 \u0645\u062e\u062a\u0644\u0641\u0629 \u0642\u0644\u064a\u0644\u0627\u064b \u0644\u0623\u0646 \u0631\u0627\u0628\u0637\u0629 \u0642\u062f \u062a\u0634\u0643\u0644\u062a \u062f\u0627\u062e\u0644 \u0627\u0644\u062c\u0632\u064a\u0621. \u0627\u0644\u0631\u0627\u0628\u0637\u0629 \u062b\u0646\u0627\u0626\u064a\u0629 \u0627\u0644\u0643\u0628\u0631\u064a\u062a \u0645\u062b\u0627\u0644 \u0639\u0644\u0649 \u0630\u0644\u0643: \u0641\u064a \u0646\u0645\u0648\u0630\u062c \u0623\u0643\u0633\u062f\u0629 \u0628\u0633\u064a\u0637\u060c \u064a\u0624\u062f\u064a \u062a\u0643\u0648\u064a\u0646 \u0631\u0627\u0628\u0637\u0629 \u0648\u0627\u062d\u062f\u0629 \u0625\u0644\u0649 \u0625\u0632\u0627\u0644\u0629 \u0630\u0631\u062a\u064a \u0647\u064a\u062f\u0631\u0648\u062c\u064a\u0646.<\/p>\n<h2>\u0645\u0627\u0630\u0627 \u064a\u062d\u062f\u062b \u0639\u0646\u062f \u062a\u0643\u0648\u064a\u0646 \u0627\u0644\u0631\u0627\u0628\u0637\u0629\u061f<\/h2>\n<p>\u064a\u0645\u0643\u0646 \u0644\u0633\u0644\u0633\u0644\u062a\u064a\u0646 \u062c\u0627\u0646\u0628\u064a\u062a\u064a\u0646 \u0645\u0646 \u0627\u0644\u0633\u064a\u0633\u062a\u064a\u0646 \u0623\u0646 \u062a\u062a\u062d\u062f\u0627 \u0639\u0628\u0631 \u0630\u0631\u0627\u062a \u0627\u0644\u0643\u0628\u0631\u064a\u062a. \u0645\u0642\u0627\u0631\u0646\u0629 \u0628\u0627\u0644\u062b\u064a\u0648\u0644\u0627\u062a \u0627\u0644\u0645\u062e\u062a\u0632\u0644\u0629 \u0627\u0644\u0645\u0642\u0627\u0628\u0644\u0629\u060c \u062a\u062d\u062a\u0648\u064a \u062b\u0646\u0627\u0626\u064a \u0627\u0644\u0643\u0628\u0631\u064a\u062a \u0627\u0644\u0646\u0627\u062a\u062c \u0639\u0644\u0649 \u0630\u0631\u062a\u064a \u0647\u064a\u062f\u0631\u0648\u062c\u064a\u0646 \u0623\u0642\u0644. \u064a\u0641\u062a\u0631\u0636 \u0647\u0630\u0627 \u0627\u0644\u062a\u0641\u0633\u064a\u0631 \u062a\u0643\u0648\u064a\u0646 \u0631\u0627\u0628\u0637\u0629 \u0645\u062d\u062f\u062f\u0629 \u062f\u0648\u0646 \u062a\u063a\u064a\u064a\u0631\u0627\u062a \u0643\u064a\u0645\u064a\u0627\u0626\u064a\u0629 \u0623\u062e\u0631\u0649\u061b \u0642\u062f \u062a\u062d\u062a\u0648\u064a \u0627\u0644\u0639\u064a\u0646\u0627\u062a \u0627\u0644\u062d\u0642\u064a\u0642\u064a\u0629 \u0639\u0644\u0649 \u0645\u062e\u0627\u0644\u064a\u0637 \u0623\u0648 \u062a\u0639\u062f\u064a\u0644\u0627\u062a \u0625\u0636\u0627\u0641\u064a\u0629.<\/p>\n<h2>\u0627\u0644\u0641\u0631\u0642 \u0627\u0644\u0645\u062d\u0633\u0648\u0628 \u0647\u0648 \u062d\u0648\u0627\u0644\u064a 2.016 Da<\/h2>\n<p>NIST gives the mass of a hydrogen-1 atom as 1.00782503223 Da. Removing two gives a calculated neutral monoisotopic mass change of \u22122.01565006446 Da. In a teaching example, a reduced peptide with neutral monoisotopic mass 2000.00000 Da would become approximately 1997.98435 Da after one such bond forms. These are illustrative numbers, not a measured batch.<\/p>\n<h2>\u0642\u062f \u062a\u0638\u0647\u0631 \u0627\u0644\u0623\u0637\u064a\u0627\u0641 \u0627\u0644\u062e\u0627\u0645 \u0641\u062c\u0648\u0629 \u0623\u0635\u063a\u0631<\/h2>\n<p>\u0625\u0630\u0627 \u0643\u0627\u0646 \u0643\u0644\u0627 \u0627\u0644\u0623\u064a\u0648\u0646\u064a\u0646 \u064a\u062d\u0645\u0644 \u0634\u062d\u0646\u0629 +2\u060c \u0641\u0625\u0646 \u0641\u062c\u0648\u0629 m\/z \u0627\u0644\u0645\u0642\u0627\u0628\u0644\u0629 \u062a\u0643\u0648\u0646 \u062a\u0642\u0631\u064a\u0628\u064b\u0627 1.007825. \u0647\u0630\u0627 \u0646\u0635\u0641 \u0641\u0631\u0642 \u0627\u0644\u0643\u062a\u0644\u0629 \u0627\u0644\u0645\u062a\u0639\u0627\u062f\u0644\u0629. \u0644\u0630\u0644\u0643\u060c \u064a\u0645\u0643\u0646 \u0623\u0646 \u062a\u0624\u062f\u064a \u0627\u0644\u0645\u0642\u0627\u0631\u0646\u0629 \u0627\u0644\u0645\u0628\u0627\u0634\u0631\u0629 \u0628\u064a\u0646 \u0643\u062a\u0644\u0629 \u0645\u062a\u0639\u0627\u062f\u0644\u0629 \u0645\u062d\u0633\u0648\u0628\u0629 \u0648\u0642\u0645\u0629 \u0623\u064a\u0648\u0646 \u062e\u0627\u0645 \u063a\u064a\u0631 \u0645\u0639\u064a\u0646\u0629 \u0625\u0644\u0649 \u0627\u0644\u0627\u0631\u062a\u0628\u0627\u0643 \u062d\u062a\u0649 \u0639\u0646\u062f\u0645\u0627 \u062a\u0643\u0648\u0646 \u0627\u0644\u0643\u064a\u0645\u064a\u0627\u0621 \u0645\u0641\u0647\u0648\u0645\u0629.<\/p>\n<h2>\u0627\u0644\u0643\u062a\u0644\u0629 \u0644\u0627 \u062a\u062b\u0628\u062a \u062a\u0631\u062a\u064a\u0628 \u0627\u0644\u0631\u0627\u0628\u0637\u0629<\/h2>\n<p>A mass consistent with one disulfide does not, by itself, identify which cysteines are connected when several are present. Bachem\u2019s FAQ also distinguishes cysteine residues from a specifically requested disulfide arrangement. For an order, provide the intended cysteine pairing, not only the letters C in the sequence. Ask what evidence supports that arrangement, and whether a reduced comparison is needed for your particular investigation.<\/p>\n<h2>\u0627\u0644\u062e\u0637\u0648\u0629 \u0627\u0644\u062a\u0627\u0644\u064a\u0629 \u0645\u0639 NHD<\/h2>\n<p>\u0627\u0628\u062f\u0623 \u0628\u0640 <a href=\"https:\/\/nhdbio.com\/ar\/%d8%a7%d9%84%d8%ae%d8%af%d9%85%d8%a7%d8%aa\/%d8%aa%d8%ae%d9%84%d9%8a%d9%82-%d8%a7%d9%84%d8%a8%d8%a8%d8%aa%d9%8a%d8%af%d8%a7%d8%aa-%d8%ad%d8%b3%d8%a8-%d8%a7%d9%84%d8%b7%d9%84%d8%a8\/\">\u0645\u0634\u0627\u0631\u064a\u0639 \u0627\u0644\u0628\u0628\u062a\u064a\u062f\u0627\u062a \u062b\u0646\u0627\u0626\u064a\u0629 \u0627\u0644\u0643\u0628\u0631\u064a\u062a<\/a>. \u0644\u0644\u062d\u0635\u0648\u0644 \u0639\u0644\u0649 \u0639\u0631\u0636 \u0633\u0639\u0631\u060c <a href=\"https:\/\/nhdbio.com\/ar\/%d8%a7%d9%82%d8%aa%d8%a8%d8%a7%d8%b3\/\">\u0623\u0631\u0633\u0644 NHD \u062a\u0633\u0644\u0633\u0644\u0643 \u0623\u0648 \u0627\u0633\u0645 \u0627\u0644\u0645\u0646\u062a\u062c \u0648\u0627\u0644\u0643\u0645\u064a\u0629 \u0648\u0627\u0644\u0645\u0633\u062a\u0646\u062f\u0627\u062a \u0627\u0644\u0645\u0637\u0644\u0648\u0628\u0629<\/a>. \u0623\u0643\u062f \u0627\u0644\u0634\u0643\u0644 \u0627\u0644\u062f\u0642\u064a\u0642 \u0648\u0627\u0644\u062c\u062f\u0648\u0649 \u0648\u0627\u0644\u0627\u062e\u062a\u0628\u0627\u0631\u0627\u062a \u0627\u0644\u0645\u062a\u0627\u062d\u0629 \u0648\u0634\u0631\u0648\u0637 \u0627\u0644\u062a\u0633\u0644\u064a\u0645 \u0642\u0628\u0644 \u0627\u0644\u0637\u0644\u0628.<\/p>\n<h2>\u0645\u0635\u0627\u062f\u0631<\/h2>\n<ul>\n<li><a href=\"https:\/\/pml.nist.gov\/cgi-bin\/Compositions\/stand_alone.pl?ele=H\">NIST: \u0627\u0644\u0643\u062a\u0644 \u0627\u0644\u0646\u0638\u064a\u0631\u064a\u0629 \u0644\u0644\u0647\u064a\u062f\u0631\u0648\u062c\u064a\u0646<\/a><\/li>\n<li><a href=\"https:\/\/www.bachem.com\/knowledge-center\/faq-frequently-asked-questions\/\">Bachem: \u0627\u0644\u0623\u0633\u0626\u0644\u0629 \u0627\u0644\u0634\u0627\u0626\u0639\u0629 \u062d\u0648\u0644 \u0645\u0648\u0627\u0635\u0641\u0627\u062a \u0627\u0644\u0628\u0628\u062a\u064a\u062f<\/a><\/li>\n<\/ul>\n<p>\u0627\u0644\u0645\u0631\u0627\u062c\u0639 \u0627\u0644\u0639\u0627\u0645\u0629 \u062a\u0634\u0631\u062d \u0627\u0644\u0645\u0648\u0636\u0648\u0639\u061b \u0648\u0647\u064a \u0644\u064a\u0633\u062a \u062f\u0644\u064a\u0644 \u062f\u0641\u0639\u0629 NHD. \u0645\u0648\u0627\u062f \u0627\u0644\u0628\u062d\u062b \u0645\u062e\u0635\u0635\u0629 \u0644\u0644\u0628\u062d\u062b \u0648\u0627\u0644\u062a\u0637\u0648\u064a\u0631 \u0648\u0627\u0644\u062a\u0635\u0646\u064a\u0639 \u0627\u0644\u0645\u062e\u062a\u0628\u0631\u064a\u060c \u0648\u0644\u064a\u0633 \u0644\u0644\u0627\u0633\u062a\u062e\u062f\u0627\u0645 \u0627\u0644\u0628\u0634\u0631\u064a \u0623\u0648 \u0627\u0644\u0628\u064a\u0637\u0631\u064a.<\/p>","protected":false},"excerpt":{"rendered":"<p>\u064a\u0645\u0643\u0646 \u0623\u0646 \u064a\u0643\u0648\u0646 \u0644\u0646\u0633\u062e\u062a\u064a\u0646 \u0645\u0646 \u0627\u0644\u0628\u0628\u062a\u064a\u062f \u0646\u0641\u0633 \u062a\u0633\u0644\u0633\u0644 \u0627\u0644\u0623\u062d\u0645\u0627\u0636 \u0627\u0644\u0623\u0645\u064a\u0646\u064a\u0629 \u0644\u0643\u0646 \u0643\u062a\u0644\u062a\u0647\u0645\u0627 \u0645\u062e\u062a\u0644\u0641\u0629 \u0642\u0644\u064a\u0644\u0627\u064b \u0644\u0623\u0646 \u0631\u0627\u0628\u0637\u0629 \u0642\u062f \u062a\u0634\u0643\u0644\u062a \u062f\u0627\u062e\u0644 \u0627\u0644\u062c\u0632\u064a\u0621. \u0627\u0644\u0631\u0627\u0628\u0637\u0629 \u062b\u0646\u0627\u0626\u064a\u0629 \u0627\u0644\u0643\u0628\u0631\u064a\u062a \u0645\u062b\u0627\u0644 \u0639\u0644\u0649 \u0630\u0644\u0643: \u0641\u064a \u0646\u0645\u0648\u0630\u062c \u0623\u0643\u0633\u062f\u0629 \u0628\u0633\u064a\u0637\u060c \u064a\u0624\u062f\u064a \u062a\u0643\u0648\u064a\u0646 \u0631\u0627\u0628\u0637\u0629 \u0648\u0627\u062d\u062f\u0629 \u0625\u0644\u0649 \u0625\u0632\u0627\u0644\u0629 \u0630\u0631\u062a\u064a \u0647\u064a\u062f\u0631\u0648\u062c\u064a\u0646.<\/p>","protected":false},"author":1,"featured_media":3112,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"pim_family_ids":"354","pim_article_type":"Peptide buying and basics","pim_evidence_level":"Technical references and labeled calculations","pim_reviewer":"Codex AI editorial","pim_reviewed_date":"2026-10-04","pim_editorial_note":"Public data and labeled teaching calculations; not NHD batch results. Confirm project and document availability.","pim_review_status":"reviewed","pim_review_reason":"Source, arithmetic, identity and search-intent checks. No independent human technical review recorded.","pim_creation_method":"AI-assisted writing, source checks and illustrated cover.","pim_sources":"[{\"title\":\"NIST: hydrogen isotopic masses\",\"url\":\"https:\/\/pml.nist.gov\/cgi-bin\/Compositions\/stand_alone.pl?ele=H\",\"note\":\"Public reference, not NHD batch evidence.\"},{\"title\":\"Bachem: peptide specification FAQ\",\"url\":\"https:\/\/www.bachem.com\/knowledge-center\/faq-frequently-asked-questions\/\",\"note\":\"Public reference, not NHD batch evidence.\"}]","footnotes":""},"categories":[20],"tags":[],"class_list":["post-3104","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-evidence-quality-guides"],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v28.0 (Yoast SEO v28.1) - https:\/\/yoast.com\/product\/yoast-seo-premium-wordpress\/ -->\n<title>A disulfide bond changes peptide mass by about 2 Da. Why? - NHD<\/title>\n<meta name=\"description\" content=\"Peptide Raw Materials and Custom Peptide Synthesis\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/nhdbio.com\/ar\/\u0631\u0627\u0628\u0637\u0629-\u062b\u0646\u0627\u0626\u064a-\u0627\u0644\u0643\u0628\u0631\u064a\u062a\u064a\u062f-\u0641\u064a-\u0627\u0644\u0628\u0628\u062a\u064a\u062f-\u0641\u0631\u0642-\u0643\/\" \/>\n<meta property=\"og:locale\" content=\"ar_AR\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"A disulfide bond changes peptide mass by about 2 Da. Why?\" \/>\n<meta property=\"og:description\" content=\"Two versions of a peptide can have the same amino-acid sequence but slightly different masses because a bond has formed inside the molecule. 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