PSL350H1 Lecture 6: PSL350 Lecture 6
15 Mar 2016
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Document Summary
Psl350 (lecture 6): post-translation modifications and axon guidance. Posttranslational modification means the chemical modification of a protein after its translation. It is one of the later steps in protein biosynthesis for many proteins: e. g. phosphorylation, de-phosphorylation. If the protein is secreted it will end up completely in the er lumen. If the protein is membrane associated stop transfer motif in the protein will stop the transfer of the protein through er membrane and will become a membrane spanning domain of the protein. Insulin is secreted from the pancreas as a preprotein (with a prepeptide) Following the cleavage of the 24 aa signal peptide results in the protein to fold into the proinsulin proprotein. Proinsulin is further cleaved yielding active insulin composed of two peptide chains linked together through disulfide bonds: numerous guidance proteins are cleaved in the extracellular matrix to serve for different goals.
