Kidney carnosinase

Margolis FL, Grillo M, Grannot-Reisfeld N, Farbman AL 1983 Purification, characterization and immunocytochemical localization of mouse kidney carnosinase. Bio chimica et Biophysica Acta 744 237-248. 

The kidney brush border also possesses a carnosine transport system and there is evidence that kidney also contains an active carnosinase (Sauerhoefer et al., 2005). There is also evidence that carnosine can influence sympathetic nervous activity in kidney (Tanida et al., 2005) as well as brown (Tanida et al., 2007) and white adipose tissue (Shen et al., 2008). Other studies have shown that carnosine has antidepressant activity in rats (Tomonaga et al., 2008). In chicks, carnosine induces hyperactivity (Tsuneyoshi et al., 2007) whereas its reverse structure (L-histidinyl-13-alanine) has sedative and hypnotic effects (Tsuneyoshi et al., 2008). The mechanisms involved in remain obscure however. 

One of the smallest naturally occurring peptides is camosine (jS-Ala-L-His) found in relatively large amounts in various animal tissues. Its exact function is not known. In the kidney an enzyme, carnosinase, hydrolyzes the peptide to its constituent amino acids. Also present in kidney is the highest in vivo concentration of cobalt, and Co complexes with carnosine are known to reversibly bind Oj. The inference is that carnosine (via its Co" complex) in kidney may control the O2 level. Further evidence is still needed for this conclusion. The extra methylene group in the -Ala moiety considerably alters the chelating properties of carnosine relative to other His-containing dipeptides (Chapter 20.2). This is particularly so with Cu" in aqueous solution where the major species is a dimer formed from the His moiety bridging the two metal centres. ... 

---