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Biomedical subjects

K Kojima

Publications and source records attributed to K Kojima.

At least 757 records · Page 42Linked to original sources
PubMed1980

Rapid chromatographic purification of dipeptidyl peptidase IV in human submaxillary gland.

Pure dipeptidyl peptidase IV (X-prolyl dipeptidyl aminopeptidase), which did not contain aminopeptidase activity at all, was rapidly prepared from the human submaxillary gland by chromatography with concanavalin A-Sepharose and Gly-Pro-NH-(CH2)6-NH-Sepharose. The entire purification took only 3 days. Aminopeptidase, which was very difficult to separate from dipeptidyl peptidase IV by various chromatographic procedures, could be completely removed by chromatography with Gly-Pro-NH-(CH2)6-NH-Sepharose. On SDS gel electrophoresis the purified enzyme gave a single band with a molecular weight of 116,000. The apparent molecular weight of the enzyme was estimated to be 225,000 by gel filtration. Therefore, the enzyme consists of two identical subunits. It did not hydrolyze Ala p-nitroanilide at all, but the hydrolysis of the p-nitroanilides of Gyl-Pro, Lys-Pro and Arg-Pro at pH 8.0 was nearly specific.

Chromatography, Gel↗
PubMed1980

Two-dimensional electrophoresis of immunoglobulin myeloma proteins in the absence of denaturing agents.

Human sera from myeloma patients were subjected to two-dimensional electrophoresis. Heterogeneity in molecular weight and in isoelectric point of the myeloma proteins were demonstrated on the protein map. The patterns of five major immunoglobulin classes differed from each other, implying that the five classes of myeloma immu,oglobulin can be distinguished by examining the two-dimensional electrophoretic patterns. Sugar content analysis suggested that differences in sialic acid content may be one of the origins of the heterogeneity of myeloma proteins observed in isoelectric focusing.

Amino Acids↗
PubMed1980

Phospholipase A in the plasma membranes in ascites hepatomas and of normal livers in rat.

Phospholipase A activities in plasma membranes (PMs), isolated from rat ascites hepatoma cells (AH 130, AH 130FN, AH 7974, and AH 7974F), were determined and compared with those in PMs isolated from normal rat livers (neonatal, resting adult, and regenerating adult livers). All the PMs had a hydrolyzing action on 1-acyl-2[14C]oleyl-sn-glycero-3-phosphoethanolamine but not on similarly labeled phosphatidylcholine. After hydrolysis, the radioactivity was recovered in both the lyso derivative and the free fatty acid produced. Thus, the presence of phospholipases A1 and A2 in the PMs, with an optimal pH around pH 9, was demonstrated. In all the hepatoma PMs, te phospholipase A2 activity was greatly reduced or almost lacking, whereas in the PMs from normal resting and growing livers strong phospholipase A2 activity was detected equally but with a specific activity higher than that of phospholipase A1. Triton X-100 treatment had an activating effect on phospholipase A1 but an inhibitory effect on phospholipase A2 of the resting liver PMs, while the same treatment was inhibitory for both the phospholipase A1 and A2, activities of the hepatoma PMs.

Aging↗
PubMed1980

The neutral and acidic glyceroglucolipids from gastric mucous barrier of rat-stomach antrum, body and forestomach.

Distribution of glyceroglucolipids in the mucous barrier of rat-stomach antrum, body and forestomach was investigated. Surface mucus lining and preformed intracellular mucus were obtained by perfusion in vivo of the ligated stomach compartments wit saline and 2 M NaCl. Lipids were extracted from dialyzed and lyophilized samples, and separated on DEAE-Sephadex into neutral and acidic fractions. The glyceroglucolipids contained in each fraction were quantified and then separated into individual components by thin-layer chromatography. Significant differences in the concentration of glyceroglucolipids in the separated areas of the stomach were found. The content of glyceroglucolipids in the antral portion of the stomach was five-times greater than that of the forestomach. The level of sulfated glyceroglucolipids was eight-times greater in the antrum as compared to the body and four-times greater as compared to the forestomach. One sulfated glyceroglucolipid was present in antral perfusates, whereas the body and forestomach contained two additional acidic glyceroglucolipids. Based on data of partial acid and alkaline methanolyses, oxidation with periodate and chromium trioxide, and methylation of the native and desulfated compound, the structure of antral glyceroglucolipid is proposed to be: SO3H(leads to 6)Glc(alpha 1 leads to 6)Glc-(alpha 1 leads to 6)Glc(alpha 1 leads to 6)Glc(alpha 1 leads to 3)-1(3)-O-alkyl-2-O-acylglycerol. The neutral glyceroglucolipid fractions from each area of the stomach were similar in composition and only variations in their concentration were observed. The data obtained suggest that the sulfated glyceroglucolipids are involved in the protection of the gastric mucosa of the antrum, since their concentration is greatest in this most acidic portion of the stomach which is also most often exposed to duodenal reflux.

Animals↗
PubMed1980

Complex fucolipids of hog gastric mucosa. Structure of the ceramide eikosahexoside.

The structure of a complex fucolipid from hog gastric mucosa containing twenty sugar residues and exhibiting blood-group (A + H) activity has been investigated. Based on the results of immunological assays, partial acid hydrolysis, sequential degradation with specific exoglycosidases, oxidation with periodate and chromium trioxide, and permethylation analysis, we suggest that the carbohydrate chain of this fucolipid contains four termini. One of the termini bears beta Gal1 leads to 4 beta GlcNAc disaccharide, two bear blood-group A determinant and one bears H determinant. Two of the branches, terminated by beta Gal1 leads to 4 beta GlcNAc and blood-group A determinant, and two terminated by blood-group A and H determinants, are linked through beta Gal1 leads to 4 beta GlcNAc1 leads to 3/6 and beta Gal1 leads to 4 beta GlcNAc1 leads to 4 beta GlcNAc1 leads to 3/6 to the galactose residue adjacent to glucosylceramide core.

ABO Blood-Group System↗
PubMed1980

Elastic fibers of pancreatic ductal systems in pancreatitis.

In an attempt to clarify the etiology of idiopathic pancreatitis, 14 cases of chronic idiopathic pancreatitis were histologically examined. A nest of small cysts consisting of cystic, distended pancreatic ductules with a complete lack of elastic fibers in the wall was observed in 3 out of 14 cases. Studies were then focused on the behavior of elastic fibers in pancreatic ductal system in 100 cases of normal pancreas, 55 cases of chronic pancreatitis and 10 cases of pancreatolithiasis. Partial hypoplasia and/or aplasia of elastic fibers in the walls of pancreatic ductules were demonstrated with a frequency of 30% in normal pancreas, 36.3% in pancreatitis and 50% in pancreatolithiasis cases. Formation of a nest of small cysts wad detected in 4 cases of normal pancreas, 3 cases of pancreatitis and 1 case of pancreatolithiasis. It was presumed that these abnormalities of elastic fibers and formation of small cysts containing inspissated secretions might act as potential etiologic or aggravating factors in pancreatitis by a mechanism of either disturbing normal pancreatic outlow or changing pressure in the duct.

Adult↗
PubMed1980

Changes in prolyl endopeptidase during maturation of rat brain and hydrolysis of substance P by the purified enzyme.

We determined changes in prolyl endopeptidase activity in developing rat brain. A new and highly sensitive fluorogenic substrate, 7-(succinyl-Gly-Pro)-4-methylcoumarinamide, was used for determination of the enzyme activity. The enzyme activity per brain increased until 2 weeks of age, and then decreased during maturation. The enzyme was purified about 7800-fold from the brain of the rat at 2 or 3 weeks of age. The enzyme has a pH optimum of 5.8 to 6.5, and an approximate molecular weight of 70,000. The enzyme activity was completely inhibited by low concentrations of diisopropylfluorophosphate and partially inhibited by high concentrations of phenylmethanesulphonylfluoride, which are potent serine protease inhibitors. Moreover, thiolblocking agents and some heavy metals also have a strong effect on the activity. Bacitracin was found to be a potent inhibitor, with an IC50 value of 2.5 x 10(-6) M at 0.5 mM of the substrate. The enzyme was proved to hydrolyze the NH2-terminal tetrapeptide. Arg1-Pro2-Lys3-Pro4, from substance P to produce the heptapeptide, Gln5-Gln6-Phe7-Phe8-Gly9-Leu10-Met11-CONH2. The Km value of the hydrolysis of substance P was 1.0 mM. This enzyme may be related to the regulation of substance P in the brain, and to the development of neurones by forming the tetrapeptide because the tetrapeptide has almost the same effect as substance P on the neurite extension of neuroblastoma.

Animals↗
PubMed1980

Comparative study of the phospholipid composition of plasma membranes isolated from rat primary hepatomas induced by 3'-methyl-4-dimethylaminoazobenzene and from normal growing rat livers.

Plasma membranes (PM's) were isolated from primary hepatomas induced in Wistar rats by 3'-methyl-4-dimethylaminoazobenzene, from nonhepatomal regions of the same rat livers, and also from various normal rat livers, including the resting and regenerating livers of adult rats and developing livers of postnatal rats. Phospholipid analyses of these PM preparations revealed the following differences in the hepatoma PM in comparison with those of the PM of normal adult resting livers: (a) decrease in the content of total phospholipids; (b) large increase in plasmalogen content; (c) relative increase of sphingomyelin and ethanolamine phospholipids, and the decrease of choline phosphoglycerides, i.e., decrease of the ratios of choline phosphoglycerides to choline phosphosphingoside and of choline-containing phospholipids to ethanolamine-containing phospholipids; (d) decrease in phosphatidylserine and phosphatidylinositol. The phospholipid composition of the PM's from normal growing livers showed definite decreases in phosphatidylserine and sphingomyelin and increases in ethanolamine phospholipids; however, no significant alteration was observed in plasmalogen content in comparison to the PM of normal adult resting livers. The PM from the nonhepatomal regions of the hepatoma-bearing livers did not show those differences observed in hepatoma PM.

Animals↗