Sterol composition and biosynthetic genes of the recently discovered photosynthetic alveolate, Chromera velia (chromerida), a close relative of apicomplexans.

Chromera velia is a recently discovered, photosynthetic, marine alveolate closely related to apicomplexan parasites, and more distantly to perkinsids and dinoflagellates. To date, there are no published studies on the sterols of C. velia.

Asparagine362 is essential for zinc binding and catalysis in the peptidase reaction of Saccharomyces cerevisiae leukotriene A₄ hydrolase.

Zinc metallopeptidases are ubiquitous enzymes with diverse cellular functions that can be found in most organisms. Leukotriene A₄ hydrolase (LTA4H; E.C.

Arginyl aminopeptidase-like 1 (RNPEPL1) is an alternatively processed aminopeptidase with specificity for methionine, glutamine, and citrulline residues.

A previously uncharacterized member of the M1 family of zinc metallopeptidases, arginyl aminopeptidase-like 1 (RNPEPL1; EC 3.4.11.

Apolactoferrin inhibits the catalytic domain of matrix metalloproteinase-2 by zinc chelation.

Lactoferrin (LTF) is a multifunctional iron-binding protein that is also capable of binding other divalent metal cations, especially Zn2+. Recent investigations indicate that lactoferrin levels are elevated in many disease conditions in which matrix metalloproteinases (MMPs), particularly MMP-2, are also elevated, suggesting that the 2 proteins may interact. This possibility was examined by determining the effect of LTF in its holo (metal-bound) and apo (metal-free) forms on the proteolytic activity of MMP-2 and other similar zinc metalloproteases.

A conserved tyrosine residue of Saccharomyces cerevisiae leukotriene A4 hydrolase stabilizes the transition state of the peptidase activity.

Saccharomyces cerevisiae leukotriene A4 hydrolase (LTA4H) is a bifunctional aminopeptidase/epoxide hydrolase and a member of the M1 family of metallopeptidases. In order to obtain a more thorough understanding of the aminopeptidase activity of the enzyme, two conserved tyrosine residues, Tyr244 and Tyr456, were altered to phenylalanine and the mutant proteins characterized by determining KM and kcat for various amino acid beta-naphthylamide substrates. While mutation of Tyr456 exhibited minimal effect on catalysis, mutation of Tyr244 caused an overall 25-100-fold reduction in catalytic activity for all substrates tested.