title: Effects of dietary proteins on linoleic acid desaturation and membrane fluidity in rat liver microsomes.
abstract: The effect of dietary protein, casein (CAS) and soybean protein (SOY), on linoleic acid desaturation in liver microsomes was studied in rats. The activity of delta 6 desaturase in total and rough endoplasmic reticula (ER and RER) was significantly higher in the CAS group than in the SOY group. In ER and smooth endoplasmic reticulum, the steady-state fluorescence anisotropy of 1,6-diphenyl-1,3,5-hexatriene, when incorporated into the membrane, was decreased in the SOY group and accompanied by a reduction in the cholesterol/phospholipid (CHOL/PL) ratio, consistent with an increase in membrane fluidity. In a separate study, the effect of varying dietary proteins, CAS, milk whey protein, egg albumin, SOY, potato protein and wheat gluten, on the relationship between the delta 6 desaturase activity and microsomal membrane fluidity was also examined. The results indicated that the dietary protein-dependent change in the liver microsomal CHOL/PL ratio affected membrane fluidity, and subsequently the activity of delta 6 desaturase in liver microsomes. However, since dietary protein influenced the delta 6 desaturase activity in RER without influencing membrane fluidity, it is possible that some regulation might have taken place at the level of enzyme synthesis.
authors.affiliation: Laboratory of Nutrition Chemistry, Kyushu University School of Agriculture, Fukuoka, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Koba
authors.forename: K
authors.initials: K
authors.lastname: Wakamatsu
authors.forename: K
authors.initials: K
authors.lastname: Obata
authors.forename: M
authors.initials: M
authors.lastname: Sugano
mesh_terms: D000818:Animals; D002364:Caseins / Q000008:administration & dosage / Q000494:pharmacology; D002784:Cholesterol / Q000378:metabolism; D004044:Dietary Proteins / Q000008:administration & dosage / Q000494:pharmacology*; D004161:Diphenylhexatriene / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism; D044943:Fatty Acid Desaturases / Q000378:metabolism; D005227:Fatty Acids / Q000378:metabolism; D005454:Fluorescence Polarization; D019787:Linoleic Acid; D008041:Linoleic Acids / Q000378:metabolism*; D050602:Linoleoyl-CoA Desaturase; D008297:Male; D008560:Membrane Fluidity / Q000187:drug effects*; D008862:Microsomes, Liver / Q000378:metabolism* / Q000648:ultrastructure; D010743:Phospholipids / Q000378:metabolism; D014674:Plant Proteins, Dietary / Q000008:administration & dosage / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D030262:Soybean Proteins; D015430:Weight Gain
chemical_list: D002364:Caseins; D004044:Dietary Proteins; D005227:Fatty Acids; D008041:Linoleic Acids; D010743:Phospholipids; D014674:Plant Proteins, Dietary; D030262:Soybean Proteins; D004161:Diphenylhexatriene; D002784:Cholesterol; D019787:Linoleic Acid; D044943:Fatty Acid Desaturases; D050602:Linoleoyl-CoA Desaturase