Tetrasodium pyrophosphate promotes light meromyosin crosslinking by microbial transglutaminase

Abstract

Phosphates are commonly included in meat processing, where oxidation is inevitable, to improve water binding. This present study attempted to reveal the interactive roles of protein oxidation and tetrasodium pyrophosphate (TSPP) on the crosslinking pattern of myosin mediated by transglutaminase (TGase). Mild oxidation at 1 mM H₂O₂ facilitated the TGase-initiated crosslinking, with the dominate crosslinking site shifted from S1 (in nonoxidized myosin) to Rod. The introduction of TSPP alleviated the oxidation stress on proteins, and was conductive to the crosslinking reaction notably at the LMM domain. The crosslinking sites in untreated myosin were identified as Gln-613 (S1) and Gln-1498 (LMM) by amino-acid sequence analysis, while strongly oxidation resulted in the loss of Gln-1498. Contrastively, four new reactive crosslinking sites were generated by TSPP, one (Gln-558/Gln-567) located on S1 and three (Gln-1362, Gln-1374, and Gln-1423/Gln-1426) on LMM. Yet, Gln-1362 was eliminated under strong oxidation at 50 mM H₂O₂.

Keywords: Coomassie brilliant blue R250, PubChem CID: 23693030; Crosslinking; Cyanogen bromide, PubChem CID: 10476; Formic acid, PubChem CID: 284; Monodansylcadaverine, PubChem CID: 4247; Myosin; N-ethylmaleimide, PubChem CID: 4362; Phenylmethylsulfonyl fluoride, PubChem CID: 4784; Protein oxidation; Tetrasodium pyrophosphate; Tetrasodium pyrophosphate, PubChem CID: 24403; Transglutaminase; Trichloroacetic acid, PubChem CID: 6421; β-Mercaptoethanol, PubChem CID: 1567.