Transketolase （TK）, a thiamine diphosphate （ThDP）-dependent enzyme, catalyzes several key reactions of nonoxidative branch of pentose phosphate pathway. TK is a homodimer with two active sites that locate at the i...Transketolase （TK）, a thiamine diphosphate （ThDP）-dependent enzyme, catalyzes several key reactions of nonoxidative branch of pentose phosphate pathway. TK is a homodimer with two active sites that locate at the interface between the contacting monomers. Both ThDP and bivalent cations are strictly needed for TK activation, just like that for all ThDPdependent enzymes. TK exists in all organisms that have been investigated. Up to now, one TK gene （TKT） and two transketolase-like genes （TKTL1 and TKTL2） have been identified in human genome. TKTL1 is reported to play a pivotal role in carcinogenesis and may have important implications in the nutrition and future treatment of patients with cancer. Research- ers have found TK variants and reduced activities of TK enzyme in patients with neurodegenerative diseases, diabetes, and cancer. Recent studies indicated TK as a novel role in the prevention and therapy of these diseases.展开更多
为探究宰后初期生鲜猪肉肌细胞微观结构和蛋白质组变化对持水能力的影响,将猪背最长肌样品按照汁液流失的高低分为高汁液流失组(High drip loss group≥5.93%, H组, n=3)和低汁液流失组(Low drip loss group≤0.81%, L组, n=3),对两组...为探究宰后初期生鲜猪肉肌细胞微观结构和蛋白质组变化对持水能力的影响,将猪背最长肌样品按照汁液流失的高低分为高汁液流失组(High drip loss group≥5.93%, H组, n=3)和低汁液流失组(Low drip loss group≤0.81%, L组, n=3),对两组样品的微观结构和蛋白质组进行比较。采用透射电镜(Transmission Electron Microscopy, TEM)观测细胞间隙,并用多肽体外标记技术(Tandem Mass Tag, TMT)鉴定高低汁液流失组间的差异蛋白。结果表明,宰后24 h时,H组的细胞外间隙极显著大于L组的细胞外间隙(P<0.01)。宰后肌肉中葡萄糖磷酸变位酶-1、热休克蛋白70(Heat shock protein 70, Hsp70)、锚蛋白、硒蛋白W和层黏连蛋白的表达量越高,汁液流失越低,持水性越好,而磷酸甘油变位酶和转酮醇酶的表达量越高,汁液流失越高,持水性越差。展开更多
Growing prevalence of diabetes(type 2 as well as type 1) and its related morbidity due to vascular complications creates a large burden on medical care worldwide. Understanding the molecular pathogenesis of chronic mi...Growing prevalence of diabetes(type 2 as well as type 1) and its related morbidity due to vascular complications creates a large burden on medical care worldwide. Understanding the molecular pathogenesis of chronic micro-, macro- and avascular complications mediated by hyperglycemia is of crucial importance since novel therapeutic targets can be identified and tested. Thiamine(vitamin B1) is an essential cofactor of several enzymes involved in carbohydrate metabolism and published data suggest that thiamine metabolism in diabetes is deficient. This review aims to point out the physiological role of thiamine in metabolism of glucose and amino acids, to present overview of thiamine metabolism and to describe the consequences of thiamine deficiency(either clinically manifest or latent). Furthermore, we want to explain why thiamine demands are increased in diabetes and to summarise data indicating thiamine mishandling in diabetics(by review of the studies mapping the prevalence and the degree ofthiamine deficiency in diabetics). Finally, we would like to summarise the evidence for the beneficial effect of thiamine supplementation in progression of hyperglycemia-related pathology and, therefore, to justify its importance in determining the harmful impact of hyperglycemia in diabetes. Based on the data presented it could be concluded that although experimental studies mostly resulted in beneficial effects, clinical studies of appropriate size and duration focusing on the effect of thiamine supplementation/therapy on hard endpoints are missing at present. Moreover, it is not currently clear which mechanisms contribute to the deficient action of thiamine in diabetes most. Experimental studies on the molecular mechanisms of thiamine deficiency in diabetes are critically needed before clear answer to diabetes community could be given.展开更多
基金the National Natural Science Foundation of China (No. 30870871).
文摘Transketolase （TK）, a thiamine diphosphate （ThDP）-dependent enzyme, catalyzes several key reactions of nonoxidative branch of pentose phosphate pathway. TK is a homodimer with two active sites that locate at the interface between the contacting monomers. Both ThDP and bivalent cations are strictly needed for TK activation, just like that for all ThDPdependent enzymes. TK exists in all organisms that have been investigated. Up to now, one TK gene （TKT） and two transketolase-like genes （TKTL1 and TKTL2） have been identified in human genome. TKTL1 is reported to play a pivotal role in carcinogenesis and may have important implications in the nutrition and future treatment of patients with cancer. Research- ers have found TK variants and reduced activities of TK enzyme in patients with neurodegenerative diseases, diabetes, and cancer. Recent studies indicated TK as a novel role in the prevention and therapy of these diseases.
文摘为探究宰后初期生鲜猪肉肌细胞微观结构和蛋白质组变化对持水能力的影响,将猪背最长肌样品按照汁液流失的高低分为高汁液流失组(High drip loss group≥5.93%, H组, n=3)和低汁液流失组(Low drip loss group≤0.81%, L组, n=3),对两组样品的微观结构和蛋白质组进行比较。采用透射电镜(Transmission Electron Microscopy, TEM)观测细胞间隙,并用多肽体外标记技术(Tandem Mass Tag, TMT)鉴定高低汁液流失组间的差异蛋白。结果表明,宰后24 h时,H组的细胞外间隙极显著大于L组的细胞外间隙(P<0.01)。宰后肌肉中葡萄糖磷酸变位酶-1、热休克蛋白70(Heat shock protein 70, Hsp70)、锚蛋白、硒蛋白W和层黏连蛋白的表达量越高,汁液流失越低,持水性越好,而磷酸甘油变位酶和转酮醇酶的表达量越高,汁液流失越高,持水性越差。
基金Supported by The Grant from the Ministry of Health of Czech Republic,No.NT13198
文摘Growing prevalence of diabetes(type 2 as well as type 1) and its related morbidity due to vascular complications creates a large burden on medical care worldwide. Understanding the molecular pathogenesis of chronic micro-, macro- and avascular complications mediated by hyperglycemia is of crucial importance since novel therapeutic targets can be identified and tested. Thiamine(vitamin B1) is an essential cofactor of several enzymes involved in carbohydrate metabolism and published data suggest that thiamine metabolism in diabetes is deficient. This review aims to point out the physiological role of thiamine in metabolism of glucose and amino acids, to present overview of thiamine metabolism and to describe the consequences of thiamine deficiency(either clinically manifest or latent). Furthermore, we want to explain why thiamine demands are increased in diabetes and to summarise data indicating thiamine mishandling in diabetics(by review of the studies mapping the prevalence and the degree ofthiamine deficiency in diabetics). Finally, we would like to summarise the evidence for the beneficial effect of thiamine supplementation in progression of hyperglycemia-related pathology and, therefore, to justify its importance in determining the harmful impact of hyperglycemia in diabetes. Based on the data presented it could be concluded that although experimental studies mostly resulted in beneficial effects, clinical studies of appropriate size and duration focusing on the effect of thiamine supplementation/therapy on hard endpoints are missing at present. Moreover, it is not currently clear which mechanisms contribute to the deficient action of thiamine in diabetes most. Experimental studies on the molecular mechanisms of thiamine deficiency in diabetes are critically needed before clear answer to diabetes community could be given.
