Quantification of lipid selectivity by membrane proteins has been previously addressed mainly from electron spin resonance studies. We present here a new methodology for quantification of protein-lipid selectivity based on fluorescence resonance energy transfer. A mutant of M13 major coat protein was labeled with 7-diethylamino-3((4'iodoacetyl)amino)phenyl-4-methylcoumarin to be used as the don...

The transfer of labeled neutral glycosphingolipids from sonicated phosphatidylcholine vesicles to erythrocyte ghosts is greatly stimulated by a nonspecific lipid transfer protein purified from beef liver. Globo-tetraglycosylceramide is transferred at a rate 40% of that for dipalmitoylphosphatidylcholine. II3-alpha-N-Acetylneuraminosyl-gangliotetraglycosylceramide is also transferred by the tran...

A 56 days grow-out experiment with three protein levels (35, 40 and 45%) and three lipid levels (5, 10 and 15%) was conducted to evaluate the optimum protein to lipid ratio for oriental river prawn (Macrobrachium nipponense). Four hundred and five prawns, with mean (± SD) weight of 1.40 ± 0.04 g were distributed in 27 glass aquaria and were fed four times daily. Results showed tha...

Lipid transfer proteins were discovered in our labe ratory as a result of studies that began with the question: How are lipid components of plasma lipoproteins taken up by the liver cell? It soon became apparent that these cells contained a cytosolic factor ( I ) , which transferred PC from one membrane to another. Upon demonstrating that the factor was nondialyzable, heat-labile, and sensitive...

The level of nonspecific lipid transfer protein in three Morris hepatomas of varying degrees of differentiation has been found to be less than 10% of the level in either host or control livers, whereas phosphatidylcholine transfer activity is slightly reduced for hepatomas compared to host livers (20 to 40%), though nearly the same as levels present in livers of non-tumor-bearing rats. Two majo...

Lipid transfer protein (LTP) activity is modulated by a distinct plasma protein termed lipid transfer inhibitor protein (LTIP). The objective of this study was to establish an assay for LTIP that could be used to quantify its activity in lipoprotein-deficient plasma. A straightforward heating protocol (56 degrees C for 60 minutes) was found to inactivate more than 90% of LTIP activity. The resp...

in this study, the energy reserves of prediapause and diapausing adult bugs were examined using colorimetric biochemical techniques to determine carbohydrates, lipids, glycogen, and protein content. to this end, 45-day-old bugs were obtained from three different sources: laboratory colony, cold-stored insects, or natural habitat. the results showed that prediapause males and females had signifi...