Bio-Synthesis is a provider of Custom Oligo Synthesis services. Oligonucleotides are synthesized as unmodified or modified chemical structures with defined sequences using a procedure known as Phosphoramidite solid-phase synthesis. Oligos which are synthesized using solid-phase phosphoramidite chemistry are often purified by high performance liquid chromatography (HPLC) or PAGE to achieve the desired purity. Synthetic DNA or RNA oligonucleotides obtained by solid-phase synthesis are employed in a majority of molecular biology applications such as PCR, real-time PCR, sequencing, site directed mutagenesis, single nucleotide polymorphism (SNP) assays, microarrays and various therapeutic applications.
Because the relative amounts of GPa and GPb largely govern the overall process of glycogen breakdown, it is important to understand the controls on the enzymes that interconvert GPa and GPb. Interconversion of GPa and GPb is accomplished by the enzyme Phosphorylase Kinase , which transfers phosphates from 2 ATPs to GPb to form GPa. Phosphorylase kinase is present in a low activity form and a high activity form. The enzyme can be activated by two mechanisms (see HERE ). First, it can be phosphorylated by Protein Kinase A (PKA). Phosphorylation of phosphorylase kinase ACTIVATES the enzyme. (Recall that PKA is activated by cAMP). Another way to activate the enzyme is with calcium. Remember that calcium is also a second messenger in the cell (in addition to cAMP) and can bind to the protein calmodulin. Calmodulin, it turns out, is a subunit of phosphorylase kinase. Activation of phosphorylase kinase by calcium is VERY important in muscle, which uses the ion to trigger musclular contraction. Thus, the same ion that stimulates muscular contraction also activates phosphorylase kinase, which activates glycogen phosphorylase, which releases G1P from glycogen, which can be used to make ATP to support muscular contraction.
The conversion of HMG-CoA to mevalonate by HMG-CoA reductase is the rate-limiting step of cholesterol biosynthesis and is under strict regulatory control (see Figure 1 ). HMGR is the target of compounds that are effective in lowering serum cholesterol levels. Human HMG-CoA reductase consists of a single polypeptide chain of 888 amino acids. The amino-terminal residues are membrane bound and reside in the endoplasmic reticulum membrane, while the catalytic site of the protein resides in its cytoplasmic, soluble carboxy-terminal portion. A linker region connects the two portions of the protein.