Protein translation and processing modification.

the
peptide
chain released from the nuclear glycogenname, according to the nature of the
amino acid
side chain in the first structure, from bamboo curling, forming a certain spatial structure, it has been believed that the formation of
protein
space structure is determined by its first-level structure, do not need additional information.
In recent years, it has been found that many in-cell proteins need the help of a class of proteins called "split bridesmaids" to complete, and the concept does not negate the principle that amino acid sequentiality determines the spatial structure of proteins. Instead, this theory is supplemented by the fact that proteins such as molecular bridesmaids can mediate other proteins into functionally active spatial structures that are not themselves involved in the composition of the final assembly product.
Currently believe that there are two types of "molecular bridesmaid" proteins, the first is some enzymes, such as protein disulfur bond isomerase can identify and hydrolyzed dismetrically incorrectly paired disulfur bonds, so that they re-form the disulfur bonds in the correct cysteine residue position, and the second is some protein molecules, they can be partially folded or not folded protein molecules binding, stabilize their composition, from other enzymes hydrolyzed or promote protein folding correct spatial structure.
In short, "molecular bridesmaids" protein synthesis folded into the correct spatial structure plays an important role, for most proteins, peptide chain translation after the following different ways of processing modification to have physiological functions.. 1. Modification of the amino and carboxyl endsAlmost all proteins in primary nuclear organisms start with N-methyl methionine, and the endural organisms start with methionine. Methyl is removed by enzyme water, and some amino acid residues at methionine or amino ends are often catalyzed by amino enzymes and removed by water. Includes the removal of the signal peptide sequence. Therefore, the mature protein molecule N-end has no methyl, or no methionine. At the same time, some protein molecular amino ends to be acetylized in the base end of the carboxyme also need to be modified.. 2. Co-price modificationMany proteins can be modified with different types of chemical groups, after modification can be shown as active state, can also be shown as inactivated state.(1)
phosphate
:Phosphate occurs mostly on polypeptide stresine, hydroxyl suline, and occasionally on tyrosine residues, a phosphate process affected by a protein in the cell
kinase
catalysis, phosphate proteins can increase or decrease their activity, for example: promote the decomposition of glycogen phosphatase, inactive phosphatase b after phosphate, become active phosphatasea. The active glycogen synthase I is phosphatized and becomes the inactive glycogen synthase D, which jointly regulates the synthesis and distribution of glycogens.(2) Glycosylation: -quality membrane proteins and many secretive proteins have sugar chains that bind to hydroxyl serine or suline, such as ABO blood type-determining clusters on red blood cell membranes. It can also be connected to Tianmen dongamide. These oligosaccharine chains are added to the endosome mesh or goerkis.(3) hydroxylation: Proline and lysine residues in the collagen pre α chain are affected by hydroxyase, molecular oxygen, and
vitamin
C in the intrasurous network to produce hydroxy proline and hydroxylycline, which greatly reduces its stress strength if the process is impaired by collagen fibers that cannot be crosslinked.(4) Formation of the two sulfur bonds: mRNA does not have cysteine codex, the polypeptide chain of the two sulfur bonds, is formed after the peptide chain synthesis, through the two cysteine dredging oxidation, the formation of the two sulfur bonds for many enzymes and protein activity is necessary.. 3. Aggregation of sub-base: many proteins are composed of more than two sub-base, which requires these peptide chains to be polymerized into polymers through non-co-priced bonds in order to express biological activity.
e.g. adult hemoglobin consists of two α-strands, two β-chains and four-molecule hemoglobin, the general process is as follows: the α chain is self-released after polyurucleosome synthesis, and has not yet been released from polyurucleucleosomes β chains, and then removed from polyucleucleomes, into α, β djubin. The djust binds to two hemoglobins produced in the mitochondrials, resulting in a functional hemoglobin molecule consisting of four peptide chains and four hemoglobins. . 4. Hydrolytic broken chain: A
gene
in a common endocycle corresponds to an mRNA, an mRNA corresponds to a peptide chain, but there are a few cases where a translated polypeptide chain is hydrolysed to produce several different proteins or peptides. For example, the original translation product of the opiate-like black skin-promoting black skin
hormone
in mammals was 265 amino acids, which in the pituitary frontal leaf cells, poMC was initially cut into N-end fragments and C-end fragments of β-lipid-promoting hormone.
then the N-side fragments are cut into smaller N-end fragments and adrenal corticosteroids of the 9 peptides. In the mid-leaf cells of the pituitary glyoph, β-lipid-promoting hormones are cut again to produce β-endorphins, and ACTH is cut to produce 13 peptides of black-promoting hormones (alphamelanotropin).
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