{
  "id": 12526685,
  "title": "Substrate accessibility of bovine milk proteins to a Pseudomonas metalloprotease reveals why caseins are more readily hydrolysed than whey proteins",
  "url": "https://urgent.news/2026/10/06/substrate-accessibility-of-bovine-milk-proteins-to-a-pseudomonas",
  "topic": "science",
  "section": "Science",
  "published": "2026-10-06T00:00:00.000Z",
  "source": {
    "name": "bioRxiv",
    "slug": "biorxiv",
    "url": "https://www.biorxiv.org/content/10.64898/2026.10.02.756230v1?rss=1"
  },
  "original_language": "en",
  "account": "A recent study has shed light on the substrate accessibility of bovine milk proteins to the Pseudomonas metalloprotease, AprX. This research reveals why caseins are more readily hydrolyzed by AprX compared to native whey proteins. The findings challenge the assumption that solvent accessibility from static protein structures accurately predicts protease cleavage sites.\n\nIn the study, six bovine milk proteins were analyzed, and sequence compatibility and local scissile-bond accessibility between caseins and whey proteins did not separate the two types. However, the researchers found that accessibility decreased progressively in whey proteins as the required contiguous substrate window increased. By the P4-P4 footprint, accessibility dropped to 0%, while all evaluatable casein windows remained accessible in isolated-chain ensembles.\n\nFurther investigation showed that local remodeling allowed whey segments to adopt backbone geometries compatible with AprX. An external thermolysin benchmark dismissed a rigid whole-protein clash metric but did not alter the contiguous-accessibility result. These findings highlight footprint-scale accessibility as a unique structural variable and demonstrate how single-residue solvent exposure can overestimate protease accessibility in folded proteins.",
  "summary": "Structure-aware proteolysis prediction often ranks candidate cleavage sites using solvent accessibility from static protein structures, yet this assumption is rarely tested against native-state cleavage data. We examined this problem using AprX, a serralysin-family protease that readily hydrolyses caseins but shows lower activity toward native whey proteins. Across six bovine milk proteins,…",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}