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1.
Current dogma of bile acid synthesis in mammals insists that hydroxylation of the ring structure at C-12 precedes side chain oxidation, and that chenodeoxycholic acid is not converted to cholic acid under normal conditions. This report concerns the conversion of chenodeoxycholic acid to cholic acid by isolated, perfused rat liver. Results indicate that isolated perfused rat liver has a definite, but limited, capacity for synthesis of cholic acid from chenodeoxycholic acid. 相似文献
2.
The hepatic metabolism of deoxycholic acid was studied using the isolated perfused rat liver technique. In 20 perfusions, 10 involving the livers of male rats and 10 involving the livers of female rats, 30 μmoles deoxycholic acid was added to the perfusion medium. In 10 perfusions, 5 male and 5 female, 1 μmole deoxycholic acid was added to the perfusion medium. In 10 of the high dose studies and in the 10 low dose studies, 1 μCi deoxycholic acid-C-24-C14 also was added. The deoxycholic acid was added to 100 ml perfusion medium after 2 hr of baseline perfusion, and the studies were continued another 3 hr. Biliary bile acids were analyzed by combined thin layer and gas chromatography, and the radioactivity content of the perfusion medium and liver was documented. Although there was no sex difference in total bile acid secretion in the high dose studies, there were sex differences in the bile acid secretion rate and in the quantitative secretion of individual bile acids. The biliary secretion of deoxycholic acid and cholic acid was immediate in the female studies and delayed in the male, and the amounts of cholic acid and sulfated deoxycholyl-taurine secreted were considerably greater in the male studies. In the low dose studies the isolated perfused liver of the female rat converted more deoxycholic acid to cholyl-taurine than did that of the male rat. There are sex differences in the hepatic metabolism of deoxycholic acid. In contrast to those found in the case of chenodeoxycholic acid, these sex differences are not impressive when physiological amounts of deoxycholic acid are presented to the liver. 相似文献
3.
Ikuo Ikeda Jun Murakami Takayuki Oka Michihiro Sugano Hideaki Yamada Sakayu Shimizu Hiroshi Kawashima Yoshifumi Shinmen Teruo Amachi 《Lipids》1991,26(1):27-30
The effects of perfused oleic (18∶1n−9), arachidonic (20∶4n−6) and 5,8,11,14-nonadecatetraenoic (19∶4n−5) acids on triglyceride
and cholesterol secretion and ketone body production were studied in isolated rat liver. As compared to oleic and 19∶4n−5
acids, both ketone body production and triglyceride secretion were significantly lowered when arachidonic acid was perfused.
The concentration of triglyceride in the post-perfused liver was lower upon perfusion with arachidonic acid than upon perfusion
with oleic acid or 19∶4n−5 acid. Cholesterol secretion in the liver perfused with arachidonic acid or 19∶4n−5 acid was significantly
higher than with oleic acid. The concentration of cholesterol in the post-perfused liver was slightly but significantly higher
with 19∶4n−5 acid than with the other fatty acids. The results suggest that 19∶4n−5 acid when compared with arachidonic acid
affects lipid metabolism in liver differently. 相似文献
4.
Zu Jun Zhang Henry G. Wilcox Lawrence Castellani Thomas V. Fungwe Marshall B. Elam Murray Heimberg 《Lipids》1993,28(5):419-425
The effects of increasing concentrations of eicosapentaenoic acid (20∶5n?3; EPA) and oleic acid (18∶1n?9; OA) on esterification to triacylglycerols (TG) and phospholipids (PL), and the relationship to formation and secretion of the very low density lipoproteins (VLDL) were compared in the isolated perfused rat liver. Mixtures of EPA and OA were also studied to determine whether substrate levels of one fatty acid might influence the metabolism of the other. The basal perfusion medium, which contained 30% (vol/vol) washed bovine erythrocytes, 6% (wt/vol) bovine serum albumin (BSA), and 100 mg glucose/dL in Krebs-Henseleit bicarbonate buffer (pH 7.4) was recycled through the liver for 2 h. EPA or OA, as a complex with 6% BSA, was infused at rates of 70, 105, 140 and 210 μmol/h. In other experiments, mixtures of EPA and oleic acid (70 μmol total), with molar percentages of 100, 75, 50, 25 and 0% of each fatty acid were infused per hour. BSA (6%) in the buffer was infused alone and served as the control. At an infusion rate of 70 μmol EPA per hour, hepatic VLDL lipid output was not different from that when fatty acid was not infused (approximately half that when 70 μmol OA/h was infused). However, when larger amounts of EPA and OA were infused individually, rates of VLDL secretion were stimulated to a similar extent with either fatty acid. The apparent inhibitory influence of EPA on TG synthesis and VLDL lipid output when 70 μmol EPA were infused per hour could also be overcome by the presence of as little as 25 mol% OA in a mixture. Furthermore, the presence of EPA in the infused fatty acid mixture stimulated the incorporation of OA into TG, enhancing VLDL secretion. When EPA or OA was infused at rates exceeding 70 μmol/h, a constant amount of endogenously-derived fatty acids was incorporated into VLDL-TG, similar in amount to that when exogenous fatty acid was not supplied. However, when EPA was infused at a rate of 70 μmol/h, incorporation of endogenous fatty acid was depressed. AT this low rate of EPA infusion, esterification of EPA and endogenous fatty acid was inhibited. Conceivably, this may reflect the existence of independently-regulated pools of fatty acid (exogenous and endogenous), in that only exogenously available fatty acid preferentially enrich the secreted TG. Enrichment of PL by the infused fatty acid at the higher rates of fatty acid infusion showed similar, but much less pronounced, differences between VLDL and liver, compared to that for TG, providing additional evidence for a distinct metabolic pool of PL used for VLDL fabrication. It now appears that when EPA is available to the liver in high enough concentrations, or when OA (or other fatty acids?) is present in substrate amounts along with EPA, competing reactions and/or specific inhibitory influences of EPA on enzymatic reactions are overcome, and EPA can be utilized in a manner similar to OA for esterification to TG with subsequent enhanced VLDL formation and secretion. 相似文献
5.
Rat liver cells, isolated by chelate perfusion and extrusion through a tissue press, incorporated labeled acetate into cellular
lipids and into lipids released into the suspending medium. Optimal rates of incorporation required supplementation of tris-KCl
medium with Mg++, Mn++, succinate, citrate, nicotinamide, Coenzyme A, NADP and glucose-6-phosphate. The rate of acetate incorporation was markedly
altered by changes in incubation media; tris-KCl was the most effective buffer. All the major classes of cellular lipids were
labeled. ATP, BSA, inorganic phosphate, Ca++, 2,4-dinitrophenol and sodium clofibrate were potent inhibitors of acetate incorporation. When added to the incubation mixture,
several hormones altered the rate of acetate incorporation into lipids. 相似文献
6.
Zu Jun Zhang Henry G. Wilcox Marshall B. Elam Lawrence W. Castellani Murray Helmberg 《Lipids》1991,26(7):504-511
The hepatic metabolism of oleic acid and n−3 fatty acids (eicosapentaenoic acid, EPA and docosahexaenoic acid, DHA), and secretion
of very low density lipoprotein (VLDL) were studied in isolated perfused rat livers from normal chow fed male rats. The basal
perfusion medium contained 30% bovine erythrocytes, 6% bovine serum albumin (BSA), and 100 mg/dL glucose, in Krebs-Henseleit
bicarbonate buffer (pH 7.4) which was recycled through the liver for 2 hr. Individual fatty acids (EPA, DHA or oleic acid),
as complexes with 6% BSA, or albumin alone, were infused at a rate of 70 μmol/hr. When any of these fatty acids was infused
at this rate, the ambient concentration in the medium was maintained at 0.3–0.4 μmol/mL, indicative of similar hepatic rates
of uptake for each fatty acid (i.e., approximately 6 μmol/g liver/hr). When fatty acid was not infused, the ambient free fatty acid level was 0.16 μmol/mL. The
concentrations of infused free fatty acids increased appropriately in the perfusion medium; however, with infusion of EPA,
DHA, or oleate, the concentrations of perfusate palmitate and linoleate were the same as when fatty acid was not infused.
Additionally, the perfusate concentration of oleate in the free fatty acid fraction was not affected by infusion of EPA and
DHA. These data indicate a constant outflow of endogenous fatty acid unaffected by the presence of the exogenously supplied
fatty acid.
The net secretion rate of VLDL lipids and protein was stimulated by infusion of oleate, whereas when EPA was infused, secretion
rates were lower and similar [except for VLDL cholesterol (C), which was greater] to those occuring when fatty acid was not
provided. DHA stimulated the secretion of VLDL triacylglycerol (TG), phospholipid (PL) and C to a similar rate, as did oleate,
but secretion of VLDL cholesteryl ester (CE) and protein was lower and similar to that with EPA. VLDL and hepatic TG and CE
were enriched with the infused fatty acids, compared to experiments without fatty acids, as determined by gas chromatography.
Enrichment of PL, however, was significant only in liver upon infusion of EPA. The formation of14CO2 and perchloric acid soluble products from [1-14C]EPA, considered separately, did not differ statistically from that obtained with [1-14C]oleate, although the mean values were higher with [1-14C]EPA. However, the sum of oxidation products derived from EPA was significantly greater than that from oleate. Incorporation
of [1-14C]EPA into TG and CE, but not into PL, was lower as compared to that from [1-14C]oleate. These lower rates of incorporation of [1-14C]EPA into VLDL lipids therefore paralleled the mass fatty acid enrichment-patterns. It may be concluded that EPA is used
to a similar extent as oleate for synthesis of PL, but is a poorer substrate for synthesis of TG. The reduced output of newly
synthesized (radioactive) PL reflected the lower hepatic output of VLDL. Since hepatic uptake of EPA, DHA or oleate was identical,
utilization of EPA for TG synthesis was less than that of oleate or DHA. Further-more, utilization of endogenous fatty acids
for TG synthesis and secretion of the VLDL was reduced in the presence of EPA. The decreased TG synthesis resulted in reduced
formation of VLDL for transport of TG from the liver. These effects taken together with an apparently increased oxidation
of EPA provide substantial evidence for a decrease in formation of VLDL and transport of TG, PL, C and CE into the circulation
in response to EPA. DHA, however, appears to be an adequate substrate for TG synthesis and stimulates VLDL secretion. The
reduced transport of CE may reflect lower selectivity of DHA by acyl-CoA; cholesterol acyltransferase for CE formation. 相似文献
7.
Trevor G. Redgrave Raul C. Maranhao Anna M. Tercyak Elizabeth C. Lincoln Henri Brunengraber 《Lipids》1988,23(2):101-105
In comparison with their precursor lipoproteins, the remnants of the triacylglycerol-rich lipoproteins are reduced in contents
of triacylglycerols and apolipoproteins AI and AIV, whereas the contents of cholesterol (free and esterified) and apolipoprotein
E are increased. In this study, lipid emulsion models of remnant lipoproteins were used to explore which of these factors
are necessary for physiological rates of remnant uptake by the perfused rat liver. Uptake rates of lipid emulsion models of
remnant lipoproteins in the presence of apolipoprotein E were similar to in vivo uptake rates.
An abstract of this work was presented at the 57th Annual Scientific Sessions of the American Heart Association, Miami, FL,
November 1984. 相似文献
8.
The purpose of this study was to investigate the hydrolysis of saturated and unsaturated triglycerides by lung lipoprotein
lipase and to measure the incorporation of triglyceride fatty acids into lung tissue lipids. Lipolytic activity was studied
in the isolated ventilated rat lung, perfused for 100 min in a recycling system with Krebs Ringer bicarbonate containing bovine
serum albumin, 5.6 mM glucose, and 1.5 or 10 mM triglyceride. Saturated triglycerides were hydrolyzed at significantly (p<0.05)
lower rates than unsaturated triglycerides; tricaprylin, trimyristin and tripalmitin were hydrolyzed at 8.1+1.8, 5.4+1.5 and
9.5+1.8 μmol free fatty acids/g dry wt/100 min, respectively, whereas triolein and trilinolein were hydrolyzed at 20.2+1.8
and 20.6+0.3 μmol free fatty acids/g dry wt/100 min, respectively. The polyunsaturated triglycerides, trilinolein and triarachidonin
were hydrolyzed at even higher rates (44.3+3.0 and 50.9+5.4 μmol free fatty acids/g dry wt/100 min, respectively). Intralipid
infused at a concentration of 10 mM triglyceride was hydrolyzed at a significantly higher rate than at 1.5 mM triglyceride
(58+6.3 μmol free fatty acids/g dry wt/100 min vs 16.6+1.7 μmol free fatty acids/g dry wt/100 min, respectively). Labeled
unsaturated triglycerides were broken down at significantly higher rates than labeled saturated triglycerides. Incorporation
of triglyceride-fatty acid into lung lipid was greater into neutral lipids than into phospholipids. The data suggest that
(a) the factors that appear to affect lung lipoprotein lipase activity are composition and concentration of circulating triglyceride,
(b) uptake of fatty acids into the tissue was proportional to the rate of hydrolysis of the emulsion, and (c) triglyceride-fatty
acids could therefore be used by the lung for metabolic needs.
The data presented in part at the Annual Meetings of the American Physiological Society, Atlanta, GA, April 1981, and the
American Thoracic Society, Detroit, MI, May 1981, and published in abstract form-Fed. Proc. 40, 621 (1981), andAm. Rev. Respir. Dis. 123, 219 (1981). 相似文献
9.
Dietary conjugated linoleic acid reciprocally modifies ketogenesis and lipid secretion by the rat liver 总被引:3,自引:0,他引:3
Sakono M Miyanaga F Kawahara S Yamauchi K Fukuda N Watanabe K Iwata T Sugano M 《Lipids》1999,34(9):997-1000
The effects of dietary conjugated linoleic acid (CLA) and linoleic acid (LA) on ketone body production and lipid secretion
were compared in isolated perfused rat liver. After feeding the 1% CLA diet for 2 wk, the concentration of post-perfused liver
cholesterol was significantly reduced by CLA feeding, whereas that of triacylglycerol remained unchanged. Livers from CLA-fed
rats produced significantly more ketone bodies; and the ratio of β-hydroxybutyrate to acetoacetate, an index of mitochondrial
redox potential, tended to be consistently higher in the liver perfusate. Conversely, cumulative secretions of triacylglycerol
and cholesterol were consistently lower in the livers of rats fed CLA, and the reduction in the latter was statistically significant.
Thus dietary CLA appeared to exert its hypolipidemic effect at least in part through an enhanced β-oxidation of fatty acids
at the expense of esterification of fatty acid in the liver. 相似文献
10.
Two groups of male Wistar rats were fed normal (i.e., 18%) and protein-free diets, respectively, for 7 weeks. In vivo incorporation
of [1-14C] acetate into palmitic, stearic, oleic, and arachidonic acids by the liver was reduced in the protein-deficient rats. In
vitro incubation of liver microsomes with labeled palmitate or linoleate revealed no change in the specific activities of
chain elongating or desaturating enzymes. Protein deficiency resulted in a decrease in specific activity of short chain acyl-CoA
synthetase and in total CoA, accompanied by the virtual disappearance of acyl-CoA and an increase in free CoA. Furthermore,
there was less microsomal fatty acid synthetase and mitochondrial β-hydroxybutyrate dehydrogenase activity. These results
are discussed in relation to fatty acid synthesis and the changes in liver fatty acid composition. 相似文献
11.
Dispersed rat liver cells were used for study of protein and serum lipoprotein synthesis. Cellular leucine incorporatein was
tested in the presence of various cofactors, buffers and inhibitors.14C-leucine was incorporated into cellular protein at an active rate for 1 hr. Incorporation was more rapid in the presence
of succinate, MgCl2, phosphate and nicotinamide, but these cofactors were not absolutely required. The liver cells also incorporated labeled
leucine into lower density lipoproteins (1DL) and released the newly labeled 1DL into the incubation medium. Puromycin strongly
inhibited the production of cellular protein and 1DL. The mode of cellular regulation of 1DL synthesis was examined. The rate
of 1DL production was selectively enhanced by short term alimentation with dietary triglyceride or by the addition of a mixture
of lipogenic cofactors to incubated liver cells. The utility of isolated liver cells as a preparation for metabolic control
studies is discussed. 相似文献
12.
The uptake of dolichol and cholesterol by perfused rat liver was studied. When these radioactive lipids were incorporated
into egg phosphatidylcholine liposomes, both dolichol and cholesterol appeared initially in the supernatant and in the microsomal
fraction and, later on, in the mitochondrial-lysosomal fraction. The lipids taken up were esterified to some extent, but no
phosphorylation of dolichol occurred. Incorporation of dolichol and cholesterol into lipoproteins increased the efficiency
of uptake, which was receptor-mediated in this case. Accumulation of these lipids occurred in lysosomes followed by a transport
to the endoplasmic reticulum (ER). Both labeled dolichol and cholesterol appeared in the bile. In the case of dolichol, the
majority of this radioactivity was not associated with the original substance itself, and probably represented lipid-soluble
catabolites. In the case of cholesterol, most of the radioactivity was associated with bile acids. It appears that, in contrast
to the receptor-mediated uptake of lipoproteins from the perfusate, the uptake of liposomal lipids involves a different mechanism.
After association with the plasma membrane, the lipids enter into the cytoplasm and are transported to the ER and later to
the lysosomes. 相似文献
13.
14.
Two groups of rats were fed diets containing 20% by weight of either partially hydrogenated marine oil supplemented with sunflower
seed oil (PHMO) or palm oil (PO) for 8 wk. Using a liver perfusion system, the effect of dietary long chain monoenoic fatty
acids on the uptake and metabolism of [14-14C]erucic acid was studied. The perfusion times were 15 and 60 min, respectively. The two groups showed equal ability for erucic
acid uptake in the liver but differed in the channeling of the fatty acids into various metabolic pathways. A higher metabolic
turnover of 22∶1 in the PHMO livers relative to the PO livers was demonstrated by an increased recovery of total [14C]labeling in the triglyceride (TG) and phospholipid (PL) fractions, already evident after 15 min of perfusion. The chainshortening
capacity was highest in the PHMO group, reflected by a higher [14C]18∶1 incorporation in both TG and PL, and increasing from 15 to 60 min of perfusion. The amount of [14C]18∶1 found in PL and TG after 60 min of perfusion of livers from rats fed PO corresponded to that shown for the PHMO group
after 15 min. The PL demonstrated a discrimination against 22∶1 compared to TG, and, when available, 18∶1 was highly preferred
for PL-synthesis.
The total fatty acid distribution in the TG, as determined by gas liquid chromatography (GLC), reflected the composition of
the dietary fats. In the total liver PL, 22∶1 and 20∶1 were present in negligible amounts, although the PHMO diet contained
12–13% of both 22∶1 and 20∶1. In the free fatty acid fraction (FFA), the major part of the radioactivity (≈80%) was [14-14C]erucic acid, and only small amounts of [14C]18∶1(<2%) were presents, even after 60 min of perfusion. The shortened-chain 18∶1 was readily removed from the FFA pool
and preferentially used for lipid esterification. 相似文献
15.
The isolated perfused rat liver technique was utilized to study the effect of biliary obstruction on the rates of uptake,
synthesis and secretion of14C-labeled cholesterol in an effort to elucidate the mechanism of hypercholesterolemia in this condition. By perfusing normal
and biliary obstructed livers with a medium containing14C-labeled acetate or14C-labeled lipoprotein cholesterol and by measuring cholesterol biosynthesis in vitro, it was possible to clarify some of the
questions concerning these aspects of lipid metabolism. The results of these studies revealed that the uptake of cholesterol
was not altered in biliary obstruction. Instead the hypercholesterolemia of biliary obstruction arises from an increased rate
of secretion of cholesterol from liver, which is accompanied by an increased rate of hepatic cholesterolgenesis. Evidence
is also presented to suggest that a substance is present in biliary obstructed blood which is capable of initiating increased
cholesterolgenesis in normal livers.
Deceased. 相似文献
16.
A comparative study of the lipid composition of isolated rat sertoli and germinal cells 总被引:1,自引:0,他引:1
The lipid composition of enriched preparations of sertoli cells and of germinal cells, isolated from the testes of mature
rats, has been investigated. Sertoli cells contained a much lower content of phospholipids (in particular, much less phosphatidylcholine
and phosphatidylethanolamine) and a higher content of triacylglycerols than did germinal cells. In addition, the Sertoli cells
had a higher ratio of esterified to unesterified cholesterol than did germinal cells. Total lipids of Sertoli cells contained
considerably lower levels of palmitic and docosa-4,7,10,13,16-pentaenoic acids and higher levels of stearic and oleic acids
than did the total lipids of germinal less palmitic and docosa-4,7,10,13,16-pentaenoic acids, more stearic and oleic acids
and also more arachidonic acid than did the corresponding lipid classes of the germinal cells. Minor differences between cell
types were also noted for the content of palmitoleic, linoleic, docosa-7,10,13,16-tetraenoic, docosa-4,7,10,13,16,19-hexaenoic
and tetracosa-9,12,15,18-tetraenoic acids. 相似文献
17.
B. Åkesson 《Lipids》1980,15(9):677-681
Lipoprotein triacylglycerol secretion was studied in isolated rat hepatocytes incubated with different albumin-bound fatty
acids and labeled glycerol. The release of labeled triacylglycerol was stimulated more by unsaturated fatty acids than by
saturated ones. When lipoprotein secretion was related to cell triacylglycerol synthesis, an effect of unsaturation was no
longer observed. Instead the secretion rate, expressed in this manner, increased with increasing fatty acid chain length.
For the first time, the secretion of molecular species of triacylglycerol has been studied. The distribution of labeled glycerol
among different species was the same in the cells and in the secreted product, indicating that different triacylglycerols
were secreted without selectivity. It is concluded that the fatty acid structure influences lipoprotein triacylglycerol secretion
and it is emphasized that the effects observed depend on the method of quantitation of the secretion rate. 相似文献
18.
Edward H. Goh 《Lipids》1980,15(9):624-630
The relationships between cholesterogenesis and the activity of HMG-CoA reductase of microsomes prepared with or without sodium
fluoride, and between changes of cholesterogenesis and microsomal sterols were studied in the isolated rat liver perfused
with or without oleic acid in the presence of AY-9944. AY-9944 inhibits the conversion of 7-dehydrocholesterol, measured colorimetrically
as “fast-acting” sterols, to cholesterol, measured colorimetrically as “slow-acting” sterols. The level of “fast-acting” sterols
is used to estimate cholesterogenesis and changes in microsomal sterols. It was observed that the activity of HMG-CoA reductase
of microsomes prepared with or without fluoride reflects the relative changes in cholesterogenesis of the perfused livers.
In addition, the amount of “fast-acting” and “slow-acting” sterols in microsomes correlates with increases in the activity
of HMG-CoA reductase and cholesterogenesis. 相似文献
19.
M. Rubin Z. Halpern A. Livoff A. Wennberg A. Tietz E. Antebi D. Lichtenberg 《Lipids》1992,27(5):321-325
This study was undertaken to determine the effect of various lipid emulsions on the hepato-biliary system in rats. Rats were
randomly divided into six groups and infused continuously for 48 hr with either long-chain triglycerides (LCT), medium-chain
triglycerides (MCT) or a mixture of MCT and LCT. One group infused with physiological saline solution served as controls.
Throughout this period the rats received a fat free dietad libitum. During the last hour of lipid infusion bile was collected for determination of bile flow and composition. Subsequently,
the rats were sacrificed and the morphology and lipid content of the liver determined. Only LCT lipid emulsions induced morphological
changes and increased liver cholesterol content. In two rats infused with radiolabeled LCT, no labeled cholesterol was found
in the liver, indicating that the excess hepatic cholesterol level may originate from enhanced cholesterol mobilization to
the liver. Biliary cholesterol and phospholipid concentrations in LCT-treated rats were also elevated, as was the lithogenic
index, whereas the other emulsions had no such effects. None of the emulsions affected the plasma liver function tests or
bile flow. We therefore conclude that the lithogenicity of the bile in rats is directly related to the lipid components of
the total parenteral nutrition and the type of triglyceride infused. 相似文献
20.
Steady-state fluorescence anisotropy of diphenylhexatriene and n-(9-anthroyloxy)stearic acids (n=2,12) in rat liver microsomes
showed a marked increase in the early stages of enzymatically or non-enzymatically induced lipid peroxidation. The changes
in fluorescence anisotropy occurred in parallel with the formation of thiobarbituric acid-reactive substances (TBA-RS). Parallel
to these changes, the fluorescence emitted from peroxidized microsomes increased markedly in the early stages of lipid peroxidation.
In contrast to the changes in the fluorescence anisotropy and in the formation of TBA-RS, the fluorescence showed a continuing
increase over the three hr period of lipid peroxidation. Glucose-6-phosphatase was inactivated in the early stages of lipid
peroxidation, whereas NADH-cytochrome b5 reductase underwent a slow deactivation over three hr. The apparently slow deactivation of the peripheral protein may be
explained by the formation of fluorescent substances. 相似文献