{"id":42736,"date":"2025-06-29T09:45:50","date_gmt":"2025-06-29T09:45:50","guid":{"rendered":"https:\/\/gaviki.com\/blog\/?p=42736"},"modified":"2025-06-29T09:45:51","modified_gmt":"2025-06-29T09:45:51","slug":"at-ph-6-0-the-charge-state-of-hsn-ch_coi-hn_ch_co2-hnn_ch_co5-ch34-ch-ch2-nh2-co2-net-1-charge-net-0-charge-net-charge-lysine-alanine-aspartic-acid-a-basic-amino-acid-neutral-amino-acid","status":"publish","type":"post","link":"https:\/\/gaviki.com\/blog\/at-ph-6-0-the-charge-state-of-hsn-ch_coi-hn_ch_co2-hnn_ch_co5-ch34-ch-ch2-nh2-co2-net-1-charge-net-0-charge-net-charge-lysine-alanine-aspartic-acid-a-basic-amino-acid-neutral-amino-acid\/","title":{"rendered":"At pH 6.0, the charge state of HSN CH_COI H;N_CH_CO2 HNN_CH_CO5 (CH3)4 CH; CH2 +NH2 CO2 net +1 charge net 0 charge net = [charge lysine alanine aspartic acid (a basic amino acid) neutral amino acid) (an acidic amino acid)"},"content":{"rendered":"\n<p>At pH 6.0, the charge state of HSN CH_COI H;N_CH_CO2 HNN_CH_CO5 (CH3)4 CH; CH2 +NH2 CO2 net +1 charge net 0 charge net = [charge lysine alanine aspartic acid (a basic amino acid) neutral amino acid) (an acidic amino acid) Homework: Indicate if the following peptides are acidic, basic, or neutral at pH = 6.0: Gly-Leu-Val Leu-Trp-Lys-Gly-Lys N-Acetyl-Asp-Val-Ser-Arg-Arg<\/p>\n\n\n\n<p><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-vivid-cyan-blue-color\">The Correct Answer and Explanation is:<\/mark><\/strong><\/p>\n\n\n\n<p>Here are the classifications for each peptide at pH 6.0:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Gly-Leu-Val:<\/strong>\u00a0Neutral<\/li>\n\n\n\n<li><strong>Leu-Trp-Lys-Gly-Lys:<\/strong>\u00a0Basic<\/li>\n\n\n\n<li><strong>N-Acetyl-Asp-Val-Ser-Arg-Arg:<\/strong>\u00a0Neutral<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Explanation<\/h3>\n\n\n\n<p>The overall charge of a peptide at a specific pH is determined by the sum of the charges on its N-terminal amino group, its C-terminal carboxyl group, and any ionizable amino acid side chains. At a pH of 6.0, we can establish the charge of these key groups. The N-terminal alpha-amino group (pKa ~9.5) will be protonated, carrying a +1 charge. The C-terminal alpha-carboxyl group (pKa ~2.5) will be deprotonated, carrying a -1 charge.<\/p>\n\n\n\n<p>For the side chains, we must consider acidic and basic amino acids. Acidic side chains like aspartic acid (pKa ~3.9) will be deprotonated and have a -1 charge. Basic side chains like lysine (pKa ~10.5) and arginine (pKa ~12.5) will be protonated, each carrying a +1 charge. Amino acids with neutral, non-ionizable side chains do not contribute to the charge.<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Gly-Leu-Val:<\/strong>\u00a0This peptide has a +1 charge at its N-terminus and a -1 charge at its C-terminus. The amino acids glycine, leucine, and valine all have non-ionizable side chains. Therefore, the net charge is (+1) + (-1) = 0, making the peptide neutral.<\/li>\n\n\n\n<li><strong>Leu-Trp-Lys-Gly-Lys:<\/strong>\u00a0This peptide has a +1 charge at the N-terminus and a -1 charge at the C-terminus. It contains two lysine residues. The side chain of each lysine is basic and will be protonated, contributing a +1 charge each. The other amino acids, leucine, tryptophan, and glycine, have neutral side chains. The total charge is (+1) + (-1) + (+1 from first Lys) + (+1 from second Lys) = +2. This positive net charge makes the peptide basic.<\/li>\n\n\n\n<li><strong>N-Acetyl-Asp-Val-Ser-Arg-Arg:<\/strong>\u00a0The N-terminus of this peptide is modified with an acetyl group. This acetylation forms an amide bond, which neutralizes the N-terminal amino group, so its charge is 0. The C-terminus has a -1 charge. The peptide contains one acidic residue, aspartic acid (-1 charge), and two basic residues, arginine (+1 charge each). Summing these charges gives (0) + (-1) + (-1 from Asp) + (+1 from first Arg) + (+1 from second Arg) = 0. The peptide has a net charge of zero and is therefore neutral. the C-terminal carboxyl group, and the side chains of any ionizable amino acids. At a pH of 6.0, we can establish the charge of these groups based on their pKa values. The N-terminus (pKa ~9-10) will be protonated and have a +1 charge. The C-terminus (pKa ~2-3) will be deprotonated and have a -1 charge.<\/li>\n<\/ol>\n\n\n\n<p>For&nbsp;<strong>Gly-Leu-Val<\/strong>, the peptide has a +1 charge at its N-terminus (Glycine) and a -1 charge at its C-terminus (Valine). The side chains of Glycine, Leucine, and Valine are all nonpolar and do not ionize, so they have a charge of 0. The total net charge is (+1) + (-1) = 0, making the peptide neutral.<\/p>\n\n\n\n<p>For&nbsp;<strong>Leu-Trp-Lys-Gly-Lys<\/strong>, the peptide has a +1 charge from the N-terminus and a -1 charge from the C-terminus. However, this peptide contains two basic Lysine (Lys) residues. The side chain of Lysine has a pKa of about 10.5. Since the pH of 6.0 is well below this pKa, both Lysine side chains will be protonated, each contributing a +1 charge. The net charge is (+1 for N-terminus) + (+1 for first Lys) + (+1 for second Lys) + (-1 for C-terminus) = +2. A net positive charge makes the peptide basic.<\/p>\n\n\n\n<p>For&nbsp;<strong>N-Acetyl-Asp-Val-Ser-Arg-Arg<\/strong>, the analysis is more complex. The N-terminus is modified with an acetyl group, which forms an amide bond. This N-acetylated group is uncharged at pH 6.0. The peptide contains one acidic residue, Aspartic acid (Asp), whose side chain (pKa ~4) is deprotonated at pH 6.0, contributing a -1 charge. It also has two basic Arginine (Arg) residues. The Arginine side chain (pKa ~12.5) is protonated at pH 6.0, with each contributing a +1 charge. Finally, the C-terminus has a -1 charge. The net charge is (0 for N-terminus) + (-1 for Asp) + (+1 for first Arg) + (+1 for second Arg) + (-1 for C-terminus) = 0. The peptide is therefore neutral.izable groups. These groups include the N-terminal amino group, the C-terminal carboxyl group, and the side chains of acidic or basic amino acids. The charge of each group depends on its pKa value relative to the solution&#8217;s pH, which in this case is 6.0.<\/p>\n\n\n\n<p>For a group to be protonated, the solution&#8217;s pH must be below its pKa. For it to be deprotonated, the pH must be above its pKa. At pH 6.0, the N-terminal amino group (pKa ~9.5) is protonated, carrying a +1 charge. The C-terminal carboxyl group (pKa ~2.5) is deprotonated, carrying a -1 charge.<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Gly-Leu-Val:<\/strong>\u00a0This peptide only has two ionizable groups: its N-terminus (+1) and its C-terminus (-1). The side chains for Glycine, Leucine, and Valine are nonpolar and do not have a charge. The total charge is (+1) + (-1) = 0. Therefore, this peptide is neutral.<\/li>\n\n\n\n<li><strong>Leu-Trp-Lys-Gly-Lys:<\/strong>\u00a0This peptide has a +1 charge from its N-terminus and a -1 charge from its C-terminus. The key additions are the two Lysine (Lys) residues. The side chain of Lysine is basic, with a pKa of about 10.5. Since the pH of 6.0 is well below this pKa, both Lysine side chains will be protonated, each contributing a +1 charge. The total net charge is calculated as (+1 from N-terminus) + (-1 from C-terminus) + (+1 from first Lys) + (+1 from second Lys) = +2. A net positive charge makes this peptide basic.<\/li>\n\n\n\n<li><strong>N-Acetyl-Asp-Val-Ser-Arg-Arg:<\/strong>\u00a0This peptide has unique modifications. The &#8220;N-Acetyl&#8221; group at the beginning means the N-terminal amino group has been modified and is no longer ionizable; its charge is 0. The C-terminus is deprotonated, contributing a -1 charge. The peptide contains one acidic residue, Aspartic acid (Asp), and two basic residues, Arginine (Arg). At pH 6.0, the Asp side chain (pKa ~3.9) is deprotonated, giving it a -1 charge. The two Arg side chains (pKa ~12.5) are both protonated, each contributing a +1 charge. The total net charge is (0 from N-acetyl) + (-1 from Asp) + (+1 from first Arg) + (+1 from second Arg) + (-1 from C-terminus) = 0. Consequently, this peptide is neutral.<\/li>\n<\/ol>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"1024\" src=\"https:\/\/gaviki.com\/blog\/wp-content\/uploads\/2025\/06\/learnexams-banner5-370.jpeg\" alt=\"\" class=\"wp-image-42737\" srcset=\"https:\/\/gaviki.com\/blog\/wp-content\/uploads\/2025\/06\/learnexams-banner5-370.jpeg 1024w, https:\/\/gaviki.com\/blog\/wp-content\/uploads\/2025\/06\/learnexams-banner5-370-300x300.jpeg 300w, https:\/\/gaviki.com\/blog\/wp-content\/uploads\/2025\/06\/learnexams-banner5-370-150x150.jpeg 150w, https:\/\/gaviki.com\/blog\/wp-content\/uploads\/2025\/06\/learnexams-banner5-370-768x768.jpeg 768w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>At pH 6.0, the charge state of HSN CH_COI H;N_CH_CO2 HNN_CH_CO5 (CH3)4 CH; CH2 +NH2 CO2 net +1 charge net 0 charge net = [charge lysine alanine aspartic acid (a basic amino acid) neutral amino acid) (an acidic amino acid) Homework: Indicate if the following peptides are acidic, basic, or neutral at pH = 6.0: [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-42736","post","type-post","status-publish","format-standard","hentry","category-quiz-questions"],"_links":{"self":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts\/42736","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/comments?post=42736"}],"version-history":[{"count":1,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts\/42736\/revisions"}],"predecessor-version":[{"id":42738,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts\/42736\/revisions\/42738"}],"wp:attachment":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/media?parent=42736"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/categories?post=42736"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/tags?post=42736"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}