1. Side reactions in peptide synthesis. V.A reexamination of the mixed anhydride method
M Bodanszky, J C Tolle Int J Pept Protein Res. 1977 Nov;10(5):380-4.
Acylation of amino acid beta-naphthylamides with protected (Boc) amino acidisobutylcarbonic acid mixed anhydrides resulted in each case in the formation of some undesired by-product: an isobutyloxycarbonylamino acid beta-naphthylamide. The amount of this second acylation product was particularly high, with the hindered amino acids valine and isoleucine as carboxyl-components. The nature of the amino component had no major influence on the extent of this side reaction.
2. Aminopeptidase from the skeletal muscle of fresh water fish Tilapia mossambica
S V Sherekar, M S Gore, V Ninjoor Indian J Biochem Biophys. 1990 Oct;27(5):316-23.
An aminopeptidase from the skeletal muscle of fish, Tilapia mossambica, was partially purified to 96-fold using salt precipitation, ion-exchange chromatography and molecular sieve chromatography. The enzyme showed optimum activity between pH 6.5-7.5 at 43 degrees C and Vmax and Km of 14.36 units/mg and 0.059 mM respectively with alanine beta-naphthylamide as the substrate. The aminopeptidase having a molecular weight of 305 kDa was activated by sulphydryl compounds and Co2+ and inhibited by bestatin, puromycin and metal chelators. Inhibition caused by metal chelators could be reversed by the addition of Co2+. Inclusion of L-amino acids, particularly isoleucine and leucine, in the assay medium caused inhibition of the enzyme activity. Substrate specificity together with inhibition and activation pattern indicated that the enzyme is alanine aminopeptidase.
