Posttranslational Covalent Modification of Proteins

Abstract

A search for derivatized amino acids in proteins has shown that the extent of posttranslational modification of proteins is quite substantial. While only 20 primary amino acids are specified in the genetic code and are involved as monomer building blocks in the assembly of the polypeptide chain, about 140 amino acids and amino acid derivatives have been identified as constituents of different proteins in different organisms. A brief consideration of the questions about where and when the derivatization reactions occur, how the specificity of the reactions is established, and how the posttranslational modifications can facilitate biological processes, reveal a need for more information on all these points. Answers to these questions should represent significant contributions to our understanding of biochemistry and cell biology.

Desmosine and isodesmosine as cross‐links in the hinge‐ligament protein of bivalves

“…Some characteristic cross-linking components have been detected in structural proteins. The desmosine analogues [4, 51 in elastin and pyridinoline [8] and lysinonorleucine in collagen are formed from lysyl residues [19], and 3,3'-bistyrosine [6, 71 in resilin is derived from tyrosyl residues. Histidinoalanine [20] and lysinoalanine [21] in collagen are expected to be formed by the reaction of histidyl and lysyl side chains, respectively, with dehydroalanyl residues, which is derived from cysteinyl or seryl residues.…”

The estimate of protein polymorphism in human populations: Lack of evidence for overestimation due to post-translational modification.

“…Theoretically, the existence of sialic acid residues and other oligosaccharide moieties attached to many proteins provide ample opportunity for post-translational modification (Uy and Wold 1977). Many of these modifications would be enzymatically mediated.…”

A novel high-capacity ion trap-quadrupole tandem mass spectrometer

“…We call this configuration the "dual tapered ion trap". The purpose of this configuration is to create in each non-linear quadrupole arm an electric potential that closely approximates (1) where (2) This potential satisfies the Laplace's equation (ΔU = 0), where the constants U 0 , r 0 , L, k and C are determined from particular initial and boundary conditions. The parameters describing the particular geometry of our trap are provided in Fig.…”

“…Detecting the presence of post-translational modifications on proteins and quantifying their abundance are prerequisites for understanding many biological processes [1][2][3]. Despite the availability of an array of techniques for the elucidation of post-translational modifications [4][5][6], their study continues to present a formidable analytical challenge.…”