Proteins making

SH Bryant, LM Amzel. Coirectly folded proteins make twice as many hydrophobic contacts. Int J Peptide Protein Res 29 46-52, 1987. 

The natural polymers known as proteins make up about 15% by mass of our bodies. They serve many functions. Fibrous proteins are the main components of hair, muscle, and skin. Other proteins found in body fluids transport oxygen, fats, and other substances needed for metabolism. Still others, such as insulin and vasopressin, are hormones. Enzymes, which catalyze reactions in the body, are chiefly protein. 

The 26 kDa protein synthesised by salt-adapted tobacco cells has been further characterised (Singh et al., 1987a). The protein makes up approximately 12% of the total cellular protein and has been resolved into two forms. These two forms have been designated osmotin 1 and osmotin II and occur in a 2 3 ratio. The forms are distinct with osmotin I soluble in an aqueous phase and osmotin II soluble in detergent. The proteins accumulate as inclusion bodies in the vacuole and are only sparsely distributed in the cytoplasm. 

Small regions of the protein make direct contact with DNA the rest of the protein, in addition to pro-... 

The demonstration that a mutation affecting the permease protein makes it insensitive to ammonia inactivation reinforces the idea that ammonia inactivation involves a chemical modification of the permease. 

The proteins are complex biological substances that make up the structural elements of the body of animals and fulfill many body functions (see Textbox 59). Each protein has different and unique functions. Their uniqueness depends on the number and order of amino acids within their polymeric chains. Proteins are required for the structure, function, and regulation of the cells, tissues, and organs of living organisms. Some proteins make up the structural elements of the body, such as specific organs, muscles, skin, blood, or part of the bones. Others perform specific body functions examples are some hormones, known as peptide hormones,... 

The primary Junction of the nucleosomes is to condense DNA. Further condensation of nucleosome DNA requires nonhistone nuclear proteins. These proteins make up a scaffoldlike structure around an additional helix consisting of coiled nucleosomes. This produces a structure that resembles a solenoid, with six nucleosome subunits per turn. The solenoid structure can form large loops that give additional structure to the incipient chromosome. 

Although the final steps of the blood clotting cascade are identical, the initial steps can occur via two distinct pathways extrinsic and intrinsic. Both pathways are initiated when specific clotting proteins make contact with specific surface molecules exposed only upon damage to a blood vessel. Clotting occurs much more rapidly when initiated via the extrinsic pathway. 

The notion of a common core structure has been further supported by synchrotron X-ray fiber diffraction patterns of several amyloid fibrils the patterns show common reflections in addition to those at 4.7 and 10 A (Sunde et al., 1997). Although these data give some insight into the arrangement of the amyloid fibril core, the exact molecular structure and organization of the proteins making up this common core have yet to be uniquely defined. The inherently noncrystalline, insoluble nature of the fibrils makes their structures difficult to study via traditional techniques of X-ray crystallography and solution NMR. An impressive breadth of biochemical and biophysical techniques has therefore been employed to illuminate additional features of amyloid fibril structure. 

In the version we used, electrophoresis of proteins makes it possible to separate proteins and evaluate molecular weight and relative amount of each fraction. Analysis of this data, therefore, has permitted us to detect the following types of modification of proteins resulting from photodynamic treatment ... 

The non-uniform behaviour of proteins makes the measurement of their molecular mass difficult however, their rough estimation and purification are very important for biochemical research. Generally, phosphate buffer and tris-HC1 buffer (pH 7) are used for SEC for biological polymers, and some additives are required for further separation. Only 0.2 m sodium phosphate buffer was... 

From the viewpoint of bioinformatics, the second observation has turned out to be most useful. The identification of a ubiquitin-like domain in a protein makes it a good candidate for a new component of the ubiquitin regulatory system. In addi-... 

The most abundant compound class found in phytoplankton and bacteria are the proteins. As shown in Table 23.3, proteins make up about half of their dry weight. In comparison to eukaryotic phytoplankton, bacteria are enriched in RNA and DNA. Because proteins and nucleic acids are relatively enriched in nitrogen as compared to carbohydrates and lipids (Table 23.4), bacterial biomass is enriched in nitrogen relative to eukaryotic phytoplankton. 

It may come as a surprise that CO is synthesized by the human body and has roles in human metabolism. Specifically, an enzyme that degrades heme, a constituent of hemoglobin, our oxygen-transporting protein, makes CO, which is a neurotransmitter. Much more about neurotransmitters follows in chapter 21 when we talk about the central nervous system. For the present, just understand that specialized cells known as neurons are the conduits for communication in the nervous system. Neurotransmitters are small molecules that relay information from one neuron to another. Neurotransmitter CO is made, functions, and is quickly destroyed. Personally, I find it surprising that CO has such a critical role in the nervous system. Surprised or not, there it is and there is no doubt about it. 

Whilst chymotrypsin and trypsin are especially useful in peptide sequence analysis, they also have medicinal applications. Their ability to hydrolyse proteins makes them valuable for wound and ulcer cleansing (trypsin) or during cataract removal (chymotrypsin). 

---