Arginine guanidinium group

First, the needle itself, amidino-piperidine, has Kj for thrombin of 150 pM and for trypsin 360 pM and thus is 2.4 x selective for thrombin. This contrasts with the classical needle benzamidine, which has fQ for thrombin of 300 pM and 31 pM for trypsin and thus is 10 X selective for trypsin. This is perhaps unexpected, as it could be argued that benzamidine, being planar, is a much better analogue of the substrate arginine guanidinium group. The width of the recognition pocket (measured from... 

The analysis of the RCSB database revealed that in almost 6% of all available structures at least one arginine guanidinium group is within 4 A of the proline imide nitrogen (Wille, G. et al., in preparation). Under nonaqueous conditions intramolecular catalysis of CTI of peptide bonds has been frequently observed... 

O Hydrolysis of the arginine guanidinium group gives urea plus ornithine, completing the cycle. 

In the final step, isourea is released from the guanidinium group of the arginine by hydrolysis (not shown), and is immediately rearranged into urea. In addition, ornithine is regenerated and returns via the ornithine transporter into the mitochondria, where it becomes available for the cycle once again. 

In 1987, Hibbs published a landmark paper in the nitric oxide field (Hibbs et al., 1987a), by demonstrating that the L-arginine that is required for CAM cytostatic activity is metabolized to L-citrulline (similar to L-arginine but less one nitrogen atom from the guanidinium group) and nitrite plus nitrate. In addition,... 

Compounds with two adjacent carbonyl groups such as 1,2-cyclohexanedione (Eq. 3-43) react selectively with guanidinium groups from arginine residues in proteins. Under certain conditions the product indicated in Eq. 3-43 predominates. Related reagents are derived from camphorquinone.284... 

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