From nucleic acids

Chemists and biochemists And it convenient to divide the principal organic substances present m cells into four mam groups carbohydrates proteins nucleic acids and lipids Structural differences separate carbo hydrates from proteins and both of these are structurally distinct from nucleic acids Lipids on the other hand are characterized by a physical property their solubility m nonpolar solvents rather than by their structure In this chapter we have examined lipid molecules that share a common biosynthetic origin m that all their carbons are derived from acetic acid (acetate) The form m which acetate occurs m many of these processes is a thioester called acetyl coenzyme A... 

Administration203 to chicks of acetic acid labeled with C14 (in the carboxyl group) gave D-glucose (from the glycogen) labeled equally at C3 and C4, but the D-ribose (from nucleic acids) had more label at C3 than at C2, indicating that in vivo D-ribose does not arise exclusively from hexose by loss of Cl. The 20-30% isotope content of D-ribose formed from D-glucose-l-C14 by Escherichia coli indicates that direct conversion is the major pathway but that a part is probably derived from transketolase action.204 206... 

Depending on diet and systemic (whole body) metabolism, which produces so-called fixed acids such as sulfate derived from sulfur-containing amino acids and phosphate, mainly from nucleic acid metabolism, there is a tendency for pH of body fluids to fall. 

Ammonia is generated mainly from the metabolism of amino acids and from the catabolism of purine and pyrimidine bases, which are produced from nucleic acids. Since it is toxic, it must be converted to a non-toxic compound for excretion from the body. This is achieved via the ornithine cycle, more usually known as the urea cycle. 

A. Salvage pathways allow synthesis of nucleotides from free purines or pyrimidines that arise from nucleic acid degradation or dietary sources, which is more economical for the cell than de novo synthesis. 

Some may say at this point that proteins derive in any case from nucleic-acid templates - perhaps through a primitive genetic code. However, this is really no argument - it merely shifts the problem of the etiology of peptide chains to etiology of oligonucleotide chains, all arithmetic problems remaining more or less the same. 

Assembly of new virus particles from nucleic acids and proteins (from steps 4 and 5)... 

Dietary purines are not an important source of uric acid. Quantitatively important amounts of purine are formed from amino acids, formate, and carbon dioxide in the body. Those purine ribonucleotides not incorporated into nucleic acids and derived from nucleic acid degradation are converted to xanthine or hypoxanthine and oxidized to uric acid (Figure 36-7). Allopurinol inhibits this last step, resulting in a fall in the plasma urate level and a decrease in the size of the urate pool. The more soluble xanthine and hypoxanthine are increased. 

Two types of pathways lead to nucleotides the de novo pathways and the salvage pathways. De novo synthesis of nucleotides begins with their metabolic precursors amino acids, ribose 5-phosphate, C02, and NH3. Salvage pathways recycle the free bases and nucleosides released from nucleic acid breakdown. Both types of... 

As they learned how proteins are made from nucleic acids, scientists developed tools to alter and map this process in order to do such things as treat human disease, uncover submicroscopic archaeologic evidence, and create new agricultural crops. All these activities come under the title of genetic engineering. 

The nucleoside formed from hypoxanthine and ribose is known as inosine (Ino or I) and the corresponding nucleotide as inosinic acid. Further substitution at C-2 of -H by -OH and tautomerization yields xanthine (Xan). Its nucleoside is xanthosine (Xao, X). A similar hydroxylation at C-7 converts xanthine to uric acid, an important human urinary excretion product derived from nucleic acid bases. 

These findings underline how combined information obtained from nucleic acid and ultrasensitive protein detection support each other to provide a valid diagnosis. 

Proteins are unstable yet their production is an inevitable step on the way from nucleic acid to life. While there is latitude in terms of the kind of proteins acquired, as concerns the functions of these proteins there are significant restrictions. Their catalytic activity must be supportive and not destructive for the parent organism. All conditions are de facto rectifiers that tend to spread uniformity. 

III. The Structure of Pyrimidine Nucleosides Derived from Nucleic Acids.. . . 285... 

Identification of the nitrogenous bases (aglycons) of pyrimidine nucleosides began at the turn of the century, when Kossel and Neumann18 isolated thymine (5-methyluracil) from nucleic acid and showed this pyrimidine to be identical with the nucleosin previously described by Miescher.19 The isolation of cytosine20 [4-amino-2()//)-pyrimidinone] and uracil21 [2,4(1, 3 )-pyrimidinedione] from the nucleic acids came shortly there-... 

Once the nucleic acids are in solution, they must be separated from the other constituents of the cell. First, the protein molecules must be removed. Many of the proteins of the cell are strongly associated with nucleic acids. The addition of sodium perchlorate (NaC104) dissociates the proteins from nucleic acids. When the mixture is shaken with the organic solvent, chloroform-isoamyl alcohol, the proteins are denatured, and they precipitate at the interface. At the same time, the lipid components of the cells are dissolved in the organic solvent. Thus the aqueous layer will contain nucleic acids, small water-soluble molecules, and even some proteins as contaminants. 

Dietmar Schomburg and Uta Lessel, Bioinformatics From Nucleic Acids and Proteins to Cell Metabolism, Contributions to the Conference on Bioinformatics, held October 9-11, 1995, in Braunschweig, Germany, in GBF Monogr., Vol. 18, VCH, Weinheim, 1995. 

Brenner, S. On the impossibility of all overlapping triplet codes in information transfer from nucleic acids to proteins. Proc. Nat. Acad. Sci. U. S. 43, 687 (1957). 

On the information transfer from nucleic acids to proteins. Biol. Medd. Dan. Vid. Selsk. 22, No. 8 (1955). 

A. Rich, and M. Yeas Problem of information transfer from nucleic acids to proteins. Advan. Biol. Med. Phys. 4, 23 (1956). 

Today, virtually all biology books speak of the genetic code, but none mentions signal transduction codes or splicing codes. Why Perhaps a brief historical summary may help us to understand. In the 1950s it became clear that protein synthesis requires a transfer of information from nucleic acids to proteins, and people realised that such a process must necessarily use a code. The existence of the genetic code, in... 

---