Lysyl group

Malin et al. (1989) reported deamination of e-amino groups of lysine in proteins tteated at pH 3.0 with high levels of nitrite. They reported deamination of 13% of the e-amino groups of poly-L-lysine at pH 5.5—6.4 during a 24-hr period, suggesting the possibility for some loss of available lysine in slightly acid, nitrite-treated foods. However, protein-lysyl groups are not a site for formation of protein-bound nitrite, since Nj gas was released as a result of lysine deamination. 

Bazaes, S. Beytia, E. Jabalquinto, A.M. Solis de Ovando, E Gomez, I. Pig liver phosphomevalonate kinase. 2. Participation of cysteinyl and lysyl groups in catalysis. Biochemistry, 19, 2305-2310 (1980)... 

Lysine tyrosylquinone (LTQ). Another copper amine oxidase, lysyl oxidase, which oxidizes side chains of lysine in collagen and elastin (Eq. 8-8) contains a cofactor that has been identified as having a lysyl group of a different segment of the protein in place of the - OH in the 2 position of topaquinone.465 Lysyl oxidase plays an essential role in the crosslinking of collagen and elastin. 

In figures 8.18 and 8.21 lysyl residues are shown in the lower right parts of the figures. An initial examination of the mechanisms indicates these lysyl groups are only observers. Why are they shown in the mechanism, and what do they do ... 

Biotin appears to have just the right chemical and structural properties to mediate carboxylation. It readily accepts activated carboxyl groups at Nl and maintains them in an acceptably stable yet reactive form for transfer to ac-ceptor substrates. Since biotin is bonded to a lysyl group,... 

Measurement of Lysyl Group Modification. The concentration of lysyl E-amino groups in collagen was determined by the method of Porter et al.(20). A fifteen mg sample of air dried collagen... 

Figure 3. Sorption of fS-galactosidase fE. coli Km) by collagen preparations at different levels of lysyl group modification...

Figure 1 illustrates the side chains of proteins useful for the formation of neoglycoproteins. Among them, the e-amino group of lysyl side chains is the most frequently used for modification of proteins, because the lysyl group is often abundant, and its side chain is flexible and solvent accessible. In the next four sections, we will describe the sugar attachment via these four functional groups. 

Fig. 15. Structure of lysyl phosphatidylglycerol. The position of linkage of the lysyl group to the glyceryl moiety (2 or 3 ) is not known.

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