Lysyl

Methoxatin, now known as coenzyme PQQ, was originally obtained from methylotrophic bacteria but is now known to be a mammalian cofactor, for example, for lysyl oxidase and dopamine p-hydroxylase. The first synthesis of this rare compound was accomplished by the route outlined below. In the retrosynthetic analysis both of the heterocyclic rings were disconnected using directly keyed transforms. 

Aminopropionitrile (present in sweet peas) covalently inactivates lysyl oxidase, preventing intramolecular cross-linking of collagen and causing abnormalities in joints, bones, and blood vessels. 

FIGURE 6.21 Collagen fibers are stabilized and strengthened by Lys-Lys cross-links. Aldehyde moieties formed by lysyl oxidase react in a spontaneous nonenzymatic aldol reaction. 

N-Carbobenzoxy-L-prolyl-e-N-p-toluenesulfonyl-L-lysyl-glycinamide N-Carbobenzoxy-L-glutaminyl-L-asparaginyl-S-benzyl-L-cysteinyl-azide N-Carbobenzoxy-S-benzyl-L-cysteinyl-L-phenylalanyl azide... 

The mixture is allowed to stand for 2 days at 20°C, after which twice its volume of ethyl-acetate is added and the resultant precipitate then washed with warm methanol. There are obtained 45 parts by weight of N-carbobenzoxy-S-benzyl-L-cysteinyl-L-phenylalanyl-L-phenylalanyl-L-glutaminyl-L-asparaginyl-S-benzyl-L-cysteinyl-L-prolyl-e-N-p-toluenesulfonyl-L-lysyl-glycinamide MP 222 C. 

Bradykinin Kallidin (lysyl-bradykinin) desArg9-bradykinin desAig10-kallidin (Lys°, desArg9-bradykinin) T-kinin (Ile-Ser-bradykinin)... 

Trypsin-like proteinases are serine proteinases that recognized peptide residues with positively charged side chains (arginyl or lysyl residues) and that effect... 

Pyridoxamine phosphate serves as a coenzyme of transaminases, e.g., lysyl oxidase (collagen biosynthesis), serine hydroxymethyl transferase (Cl-metabolism), S-aminolevulinate synthase (porphyrin biosynthesis), glycogen phosphoiylase (mobilization of glycogen), aspartate aminotransferase (transamination), alanine aminotransferase (transamination), kynureninase (biosynthesis of niacin), glutamate decarboxylase (biosynthesis of GABA), tyrosine decarboxylase (biosynthesis of tyramine), serine dehydratase ((3-elimination), cystathionine 3-synthase (metabolism of methionine), and cystathionine y-lyase (y-elimination). 

Kainate Receptor Kallidin, Lysyl-Bradykinin Kallikrein KCNQ-Channels KCOs... 

---