{"id":1959,"date":"2024-03-03T17:45:03","date_gmt":"2024-03-03T17:45:03","guid":{"rendered":"https:\/\/cake.appscodestudio.com\/?p=1959"},"modified":"2024-03-03T17:45:04","modified_gmt":"2024-03-03T17:45:04","slug":"physicochemical-properties-of-the-amino-acids","status":"publish","type":"post","link":"https:\/\/cake.appscodestudio.com\/index.php\/2024\/03\/03\/physicochemical-properties-of-the-amino-acids\/","title":{"rendered":"Physicochemical properties of the amino acids"},"content":{"rendered":"\n

The physicochemical properties of a protein are determined by the\u00a0analogous\u00a0properties of the amino acids in it.<\/p>\n\n\n\n

The \u03b1-carbon\u00a0atom\u00a0of all amino acids, with the exception of glycine, is asymmetric; this means that four different chemical entities (atoms or groups of atoms) are attached to it. As a result, each of the amino acids, except glycine, can exist in two different spatial, or geometric, arrangements (i.e.,\u00a0isomers), which are mirror images akin to right and left hands.<\/p>\n\n\n\n

These isomers exhibit the property of\u00a0optical\u00a0rotation. Optical rotation is the rotation of the plane of polarized light, which is composed of light waves that vibrate in one plane, or direction, only. Solutions of substances that rotate the plane of polarization are said to be optically active, and the degree of rotation is called the optical rotation of the\u00a0solution. The direction in which the light is rotated is generally designed as plus, or\u00a0d<\/em>, for dextrorotatory (to the right), or as minus, or\u00a0l<\/em>, for levorotatory (to the left). Some amino acids are dextrorotatory, others are levorotatory. With the exception of a few small proteins (peptides) that occur in\u00a0bacteria, the amino acids that occur in proteins are\u00a0L-amino acids.\"Proteins.<\/p>\n\n\n\n

In bacteria,\u00a0D-alanine and some other\u00a0D-amino acids have been found as components of gramicidin and bacitracin. These peptides are\u00a0toxic\u00a0to other bacteria and are used in medicine as\u00a0antibiotics. The\u00a0D-alanine has also been found in some peptides of bacterial membranes.Britannica QuizMedical Terms and Pioneers Quiz<\/p>\n\n\n\n

In contrast to most organic acids and amines, the amino acids are insoluble in organic solvents. In aqueous solutions they are dipolar ions (zwitterions, or hybrid ions) that react with strong\u00a0acids\u00a0or\u00a0bases\u00a0in a way that leads to the neutralization of the negatively or positively charged ends, respectively. Because of their reactions with strong acids and strong bases, the amino acids act as buffers\u2014stabilizers of\u00a0hydrogen ion\u00a0(H+<\/sup>) or hydroxide\u00a0ion\u00a0(OH\u2212<\/sup>) concentrations. In fact, glycine is frequently used as a\u00a0buffer\u00a0in the pH range from 1 to 3 (acid solutions) and from 9 to 12 (basic solutions). In\u00a0acid\u00a0solutions, glycine has a positive charge and therefore migrates to the\u00a0cathode\u00a0(negative electrode of a direct-current electrical circuit with terminals in the solution). Its charge, however, is negative in alkaline solutions, in which it migrates to the\u00a0anode\u00a0(positive electrode). At pH 6.1 glycine does not migrate, because each\u00a0molecule\u00a0has one positive and one negative charge. The pH at which an\u00a0amino acid\u00a0does not migrate in an electrical field is called the isoelectric point. Most of the monoamino acids (i.e., those with only one amino group) have isoelectric points similar to that of glycine. The isoelectric points of aspartic and glutamic acids, however, are close to pH 3, and those of\u00a0histidine,\u00a0lysine, and arginine are at pH 7.6, 9.7, and 10.8, respectively.<\/p>\n","protected":false},"excerpt":{"rendered":"

The physicochemical properties of a protein are determined by the\u00a0analogous\u00a0properties of the amino acids in it. The \u03b1-carbon\u00a0atom\u00a0of all amino acids, with the exception of glycine, is asymmetric; this means that four different chemical entities (atoms or groups of atoms) are attached to it. As a result, each of the amino acids, except glycine, can […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5],"tags":[],"class_list":["post-1959","post","type-post","status-publish","format-standard","hentry","category-proteins"],"Cooking_time":"","jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/cake.appscodestudio.com\/index.php\/wp-json\/wp\/v2\/posts\/1959","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/cake.appscodestudio.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/cake.appscodestudio.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/cake.appscodestudio.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/cake.appscodestudio.com\/index.php\/wp-json\/wp\/v2\/comments?post=1959"}],"version-history":[{"count":1,"href":"https:\/\/cake.appscodestudio.com\/index.php\/wp-json\/wp\/v2\/posts\/1959\/revisions"}],"predecessor-version":[{"id":1960,"href":"https:\/\/cake.appscodestudio.com\/index.php\/wp-json\/wp\/v2\/posts\/1959\/revisions\/1960"}],"wp:attachment":[{"href":"https:\/\/cake.appscodestudio.com\/index.php\/wp-json\/wp\/v2\/media?parent=1959"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cake.appscodestudio.com\/index.php\/wp-json\/wp\/v2\/categories?post=1959"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cake.appscodestudio.com\/index.php\/wp-json\/wp\/v2\/tags?post=1959"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}