|Milk Fraction||MFGM, Exosome|
|Amino Acid Lenth||199|
|Protein Existence Status||Reviewed: Experimental evidence at transcript level|
|Presence in other biological fluids/tissue/cells||expression of Prx1 in Cytosol, nucleus; prx2 in Cytosol, membrane; prx3 in Mitochondria; prx4 in Cytosol, Golgi, secreted; prx5 in Mitochondria, peroxisome, cytosol; prx 6 in Cytosol|
|Protein Function||Peroxiredoxins (Prxs) are a ubiquitous family of cysteine-dependent peroxidase enzymes that play dominant roles in regulating peroxide levels within cells; the peroxidase activity of Prx enzymes towards H2O2, organic hydroperoxides and peroxynitrite is critical to protect cellular components from oxidative damage; play cytoprotective antioxidant role in inflammation|
|Biochemical Properties||Mammalian cells express six Prx isoforms (PrxI to PrxVI), which can be classified into 2-Cys (PrxI to PrxIV), atypical 2-Cys (PrxV), and 1-Cys (PrxVI) subfamilies;hydrogen peroxide caused rapid inactivation of human Prx I by hyperoxidation during catalytic turnover; cysteine-based peroxidases that do not require any special cofactors for their activity; a peroxidatic Cys (CP) thiolate (CP-S−) attacks a hydroperoxide substrate and is oxidized to a CP-sulfenic acid (CP-SOH); In mammals, Prx1 subfamily enzymes are in the cytosol and nucleus (PrxI and PrxII), the mitochondria (PrxIII) and the endoplasmic reticulum (PrxIV); In Prxs, the CP pKa values determined for nearly a dozen representatives are clustered between 5.1 and 6.3; 83% of the CP residues being present in the thiolate form at pH 7; Factors promoting oligomerization in typical 2-Cys Prxs include high  or low [34,39] ionic strength, low pH , high magnesium  or calcium [41,42] concentrations, reduction of the redox-active disulfide center [20,22,36], and ‘overoxidation’ of the peroxidatic cysteine to a sulfinic acid|
|Significance in milk||induce the oxidation of various leuco compounds by hydrogen peroxide - distinguishes between raw and boiled milk; milk sterilized at or above 80’ C, do not show the peroxidase reaction; whereas raw milks, as a class, do give the reaction;|
|PTMs||phosphorylation of mammalian PrxI, PrxII, PrxIII and PrxIV at the conserved residue Thr89 (PrxII numbering) by cyclin-dependent kinases ;lipid raft associated prx1 undergoes phosphorylation at Tyr194; centrosomeassociated PrxI through phosphorylation at Thr9;|
|Significance of PTMs||phosphorylation leads to inactivation of this enxyme|
|Linking IDs||Bomi2505 Bomi2506 Bomi2507|
|Bibliography||1. Kappeler, S. R., Heuberger, C., Farah, Z., & Puhan, Z. (2004). Expression of the peptidoglycan recognition protein, PGRP, in the lactating mammary gland. Journal of Dairy Science, 87(8), 2660–2668. https://doi.org/10.3168/jds.S0022-0302(04)73392-5. |
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