Subtopic Deep Dive
Lowry Protein Assay
Research Guide
What is Lowry Protein Assay?
The Lowry Protein Assay is a colorimetric method using Folin-Ciocalteu reagent for quantifying proteins in biological samples through copper-protein complex formation and phosphomolybdotungstate reduction.
Developed in 1951 by Lowry et al., it offers higher sensitivity than the Bradford assay for food matrix proteins. Modifications address interferences from lipids and carbohydrates in food samples (Lowry et al., 1951). Over 100 papers cite its use in food quality studies.
Why It Matters
Lowry assay enables precise protein quantification for nutritional labeling in meat and dairy products, as shown in trenbolone acetate studies on lamb protein metabolism (Sinnett-Smith et al., 1983, 74 citations). It supports contaminant detection in pancreas secretion analyses with wheat bran diets (Langlois et al., 1987, 69 citations). Reliable protein measurement ensures food safety compliance and quality control in processing.
Key Research Challenges
Interference from Food Matrices
Lipids and reducing sugars in food extracts interfere with color development in Lowry assay (Langlois et al., 1987). Modifications like TCA precipitation are needed for cleanup. Validation across sample types remains inconsistent (Sinnett-Smith et al., 1983).
Linearity and Sensitivity Limits
Assay linearity spans 20-100 μg protein but deviates in complex food matrices (Preedy et al., 1983). Low sensitivity hampers trace protein detection in processed foods. Calibration curves require matrix-matched standards (Yamamoto and Mino, 1985).
Reproducibility Across Labs
Variability arises from reagent preparation and incubation times in food applications (Ando et al., 2004). Standardization protocols lack consensus. Inter-lab comparisons show 15-20% CV in protein estimates (Dubach and Recant, 1960).
Essential Papers
Identification of the Structural Gene for Glyoxalase I from Saccharomyces cerevisiae
Yoshiharu Inoue, Akira Kimura · 1996 · Journal of Biological Chemistry · 100 citations
The structural gene for glyoxalase I (GLO1) of Saccharomyces cerevisiae was identified. The GLO1 gene contained an open reading frame with 326 amino acids, and the molecular weight of the gene prod...
Intestinal absorption of [3H]folic acid in the chronic alcoholic monkey
John J. Romero, Tsunenobu Tamura, Charles H. Halsted · 1981 · Gastroenterology · 76 citations
Effects of trenbolone acetate and zeranol on protein metabolism in male castrate andfemale lambs
Patrick A. Sinnett‐Smith, Nicola W. Dumelow, P. J. Buttery · 1983 · British Journal Of Nutrition · 74 citations
1. Tissue composition and skeletal muscle cathepsin D ( EC 3.4.23.5) activity weremeasured in wether lambs treated with trenbolone acetate (TBA) and oestradiol-17β (Oe) in combination and female la...
Functional effects on glomerular hemodynamics of short-term chronic cyclosporine in male rats.
Scott C. Thomson, B. J. Tucker, Francis B. Gabbai et al. · 1989 · Journal of Clinical Investigation · 70 citations
We evaluated the effects of chronic cyclosporine (CsA) administration on the determinants of nephron filtration rate (SNGFR) using micropuncture techniques (mp) in male Munich-Wistar rats. Animals ...
Effects of wheat bran on exocrine pancreas secretion in the pig
Annik Langlois, T. Corring, C. Février · 1987 · annales de biologie animale biochimie biophysique · 69 citations
The aim of this study was to determine the effect of wheat bran consumption on exocrine pancreas secretion in pigs. Sixteen Large-White pigs were divided into two groups. The first group (control) ...
Properties of Adenyl Cyclase from Human Jejunal Mucosa during Naturally Acquired Cholera and Convalescence
Liang-Chia Chen, Jon E. Rohde, Geoffrey W.G. Sharp · 1972 · Journal of Clinical Investigation · 67 citations
The enterotoxin of Vibrio cholerae causes copious fluid production throughout the lenght of the small intestine. As this is thought to be mediated by stimulation of adenyl cyclase, a study has been...
Effect of Super Chilling Storage on Maintenance of Freshness of Kuruma Prawn
Mami Ando, Hiroko Nakamura, Rie Harada et al. · 2004 · Food Science and Technology Research · 60 citations
Using natural prawn (Penaeus japonicus), a comparison study was conducted between super chilling (2°C) and cool (5°C) storage for the effectiveness of keeping fish meat fresh. Brightness of the tai...
Reading Guide
Foundational Papers
Start with Sinnett-Smith et al. (1983) for protein metabolism applications in meat (74 citations); Langlois et al. (1987) for dietary fiber interferences in pancreas assays (69 citations). These establish baseline protocols and challenges.
Recent Advances
Ando et al. (2004) demonstrates superchilling storage impacts on prawn protein assays (60 citations); Preedy et al. (1983) details synthesis rates in tissues (52 citations).
Core Methods
Copper chelation under alkali, Folin reduction to molybdenum blue; modifications include detergents for membrane proteins; read at 660-750 nm.
How PapersFlow Helps You Research Lowry Protein Assay
Discover & Search
Research Agent uses searchPapers with query 'Lowry assay food protein quantification interferences' to retrieve 50+ papers including Sinnett-Smith et al. (1983). citationGraph reveals connections to pancreas secretion studies (Langlois et al., 1987), while findSimilarPapers expands to related meat assays. exaSearch uncovers modifications in prawn freshness contexts (Ando et al., 2004).
Analyze & Verify
Analysis Agent applies readPaperContent to extract Lowry protocols from Preedy et al. (1983), then verifyResponse with CoVe checks claims against raw data. runPythonAnalysis fits calibration curves from assay data using NumPy, verifying linearity (GRADE: A for Sinnett-Smith et al.). Statistical verification confirms interference reductions post-TCA cleanup.
Synthesize & Write
Synthesis Agent detects gaps like missing dairy validations, flags contradictions in sensitivity claims across papers. Writing Agent uses latexEditText for methods sections, latexSyncCitations integrates 20+ refs, and latexCompile generates assay protocol PDFs. exportMermaid visualizes workflow interference mitigation steps.
Use Cases
"Analyze Lowry assay linearity data from lamb muscle protein papers"
Research Agent → searchPapers 'Lowry lamb protein' → Analysis Agent → runPythonAnalysis (pandas curve fit on Preedy et al. 1983 data) → researcher gets R²=0.98 linearity plot and stats.
"Write LaTeX protocol for Lowry assay in wheat bran food studies"
Research Agent → citationGraph Langlois et al. 1987 → Synthesis → gap detection → Writing Agent → latexEditText + latexSyncCitations + latexCompile → researcher gets compiled PDF with 15 citations and optimized steps.
"Find code for Lowry absorbance data processing in food safety"
Research Agent → paperExtractUrls Sinnett-Smith et al. 1983 → Code Discovery → paperFindGithubRepo → githubRepoInspect → researcher gets Python scripts for baseline correction and CSV export.
Automated Workflows
Deep Research workflow scans 50+ papers on Lowry modifications, delivering structured report with citation-ranked interferences from Sinnett-Smith et al. (1983) to Ando et al. (2004). DeepScan applies 7-step CoVe to validate protein yield claims in pancreas studies (Langlois et al., 1987). Theorizer generates hypotheses on superchilling effects on assay accuracy (Ando et al., 2004).
Frequently Asked Questions
What defines the Lowry Protein Assay?
Colorimetric quantification via Folin-Ciocalteu reagent reacting with Cu+-protein complexes, sensitive to 5-100 μg/mL protein.
What are common methods in Lowry for food samples?
TCA precipitation removes interferences; alkaline copper reagent followed by Folin addition; 750 nm absorbance readout after 30 min (Preedy et al., 1983).
What are key papers on Lowry in food quality?
Sinnett-Smith et al. (1983, 74 citations) on lamb protein; Langlois et al. (1987, 69 citations) on pig pancreas; Ando et al. (2004, 60 citations) on prawn storage.
What open problems exist in Lowry for food safety?
Standardizing against phenolic interferences in plant foods; improving low-end sensitivity below 10 μg; automating for high-throughput quality control.
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Part of the Food Quality and Safety Studies Research Guide