• 대한약리학회지
• /
• 제16권2호
• /
• pp.15-24
• /
• 1980

[${\alpha}$]-Amylase catalyses the hydrolysis of starch, glycogen, and related poly- and oligosac-charide by random cleavage of ${\alpha}$-D-(l-4) glucan linkage. In man large amounts of amylase are secreted into the digestive tract by the salivary and exocrine pancreatic gland, minimal amount being produced also in other tissues. It has been known that ${\alpha}$-amylase exists in multiple molecular forms, isoenzyme which can be separated from each other because of difference in their physicochemical properties. By using various methods, several groups of investigator have separated the many isoenzyme in serum, saliva and pancreatic juice. Furthermore, changes of the normal serum isoenzyme pattern is diagnostically useful even when the total serum enzyme activity is noninformative, such as the clinical use of isoenzyme of serum lactate dehydrogenase. Procarboxypeptidase-A which is one of the pancreatic enzymes is also present as isoenzymes. Four forms of procarboxypeptidase-A haye been found in the bovine enzyme and three forms of the porcine enzyme. In human pancreatic juice four forms of procarboxypeptidase-A isoenzyme were found by isoelectric focusing method. Recently, the so-called isoamylase analysis was developed for the diagnostic use of amylase in pancreatic diseases. In alcohotic patients, the serum concentration of pancreatic isoamylase is subnormal and this lowered activity provides strong evidence for pancreatic exocrine insufficiency. The purpose of this study was to elucidate the variations of the isoenzyme of amylase and procarboxypeptidase-A in serum, saliva and pancreatic juice of the experimental animals. The results are as follow. 1) Three main forms of isoenzyme of amylase by isoelectric focusing were found in pancreatic juice of normal rabbit. However, many new bands were appeared in the pancreatic juice of cholic acid administered animal intravenously while the infusion of cholic acid or elastase into pancreatic duct produced the decrease of number of the fractions on the isoelectric focusing. In the case of serum isoenzyme from normal animal, two major and a few minor isoamylases were observed. By injecting alcohol intravenousely the fractions of serum isoamylase were significantly decreased and in contrary to the pattern in the pancreatic juice the infusion of cholic acid or elastase into pancreatic duct exhitited a significant decrease of the isoenzyme of amylase fractions. In saliva from normal animal three main isoamylase were produced of the administration of alcohol. 2) In the case of procarboxypeptidase-A isoenzyme, two major fractions which have isoelectric point at 6.2 and 6.4 and other two minor bands were observed in the pancreatic juice of normal rabbit. By the treatment of the juice with trypsin, only one band was produced on the isoelectric focusing. No procarboxypeptidase was appeared on the electrofocusing by the infusion of cholic acid or phospholipase A into the pancreatic duct of rabbit. However, a single major fraction of procarboxypeptidase-A was appeared at 3 hr after simple ligation of the pancreatic duct. No significant changes were observed in the juice of the alcohol or cholic acid administered group.

• 한국식품영양과학회지
• /
• 제27권3호
• /
• pp.367-375
• /
• 1998

The physicochemical properties of the $\alpha$-amylase inhibitors from black bean and naked barley is Korea were investigated. Preincubation time for maximum inhibition was 30min and no activity change was seen after that time. Optimum pH of the $\alpha$-amylase inhibitors from the black bean and naked barley was pH 7.0 and the inhibitory activities were stable in the range of pH 6.0~8.0 in both phosphate and Tris-HCI buffer solutions. Both inhibitors maintained more than 50% of activity after incubation for 17 min at 7$0^{\circ}C$. The inhibitors from the black bean and naked barley maintained more than 50% of activities after treatment for 40 min and 30 min with pepsin, and 30 min and 50 min with trypsin, respectively. Both inhibitors functioned via a noncompetitive mechanism and were active against porcine pancreatic and human salivary $\alpha$-amylases. The activities of both inhibitors were linear for the ionic stength ranging from 0 to 0.9. The addition of 70 mM maltose to the reaction mixture caused a maximum increase in the relative activities of both inhibitors, but it did not affect the dissociation of the EI complex. The activities of both inhibitors were significantly enhanced by adding 1mM of K+ or Mg2+.

• 대한한의학방제학회지
• /
• 제27권3호
• /
• pp.223-236
• /
• 2019

Dengropanax morfiferus (D), Broussonitia kazinoki (B), and Cudriania tricuspidata (E), a widely cultivated species in South Korea, has been used as traditional medicine to treat numerous diseases. In this study, we evaluated the antidiabetic effects in a various signaling mechanisms using mixed extract and major component contents were analyzed by HPLC in the combined extracts from Dengropanax morfiferus, Broussonitia kazinoki, and Cudriania tricuspidata (DBCE). DBCE inhibited ${\alpha}$-glucosidase and ${\alpha}$-amylase activation and showed potent antioxidant effects, which are evaluated using DPPH, ABTS, and SOD assay. Cytokines, which are released by inflammatory cells in pancreatic islets, are involved in the pathogenesis of type 1 diabetes mellitus. DBCE showed the protective effects in RINm5F cells against cytokines-induced damage by suppressing inducible nitric oxide (NO) synthase and COX-2 expression and NO production. Insulin resistance is the primary characteristic of type 2 diabetes. Therefore, the regulatory effect of DBCE on glucose uptake and production are investigated in insulin-responsive human HepG2 cells. DBCE stimulated glucose uptake, prevented Glut2 and phosphor-IRS1 downregulation induced by high glucose (HG, 30 mM). Moreover, DBCE pretreatment diminished glucose levels, PEPCK and G6Pase overexpression provoked by HG. These findings suggest that DBCE might be used for diabetes treatment through alpha-glucosidase or alpha-amylase activity regulation, pancreatic beta cell protection, hepatic glucose sensitivity improvement. Cytokines, which are released by inflammatory cells' infiltrations around the pancreatic islets, are involved in the pathogenesis of type 1 diabetes mellitus.

• Applied Biological Chemistry
• /
• 제48권4호
• /
• pp.375-381
• /
• 2005

본 연구는 흰쥐와 과체중인에서 솔잎, 홍차 및 녹차 추출물의 항-비만효과와 관련기전을 알아보기 위하여 시행되었다. 흰쥐는 무작위로 솔잎, 홍차, 녹차 및 추출물 혼합물 군으로 분류되었다. 대조군은 흰쥐 chow 식이로 사육되었으며 추출물군은 각각 0.5, 1, 2, 4 및 8% 추출물을 흰쥐 chow 식이에 첨가하여 5주간 사육하였다. 추출물 혼합물은 솔잎 :홍차 :녹차를 2 : 1 : 1의 비율로 만들어 흰쥐 chow 식이에 첨가하여 제조하였다. 솔잎과 혼합물 추출물 1, 2, 4 및 8% 첨가군은 대조군에 비하여 유의하게 체중과 내장지방을 감소시켰다. 홍차와 녹차추출물 1, 2, 4% 첨가군은 대조군에 비하여 유의하게 체중과 내장지방을 감소시켰다. 추출물 혼합군이 다른 군에 비해서 체중과 내장지방 감소효과가 컸다. 5주간의 식이동안 총 식이 섭취량은 녹차 및 홍차 8% 첨가군을 제외하고는 그룹간 차이가 없었다. 5주간의 식이에서 총 변량은 솔잎, 녹차 및 추출물 혼합 1, 2, 4% 첨가군에서 대조군보다 많았다. 과체중인에서는 추출물 혼합물이 대조군에 비하여 체중과 체지방을 유의하게 감소시켰다. 솔잎, 홍차 및 녹차의 작용기전을 알아보기 위한 시험관실험에서 솔잎은 췌장의 lipase 및 ${\alpha}-amylase$ 활성도를 억제하지 않았다. 반면에 홍차와 녹차는 농도 의존적으로 췌장의 lipase 및 ${\alpha}-amylase$ 활성도를 억제하였다. ${\alpha}-amylase$의 억제효과는 홍차가 녹차보다 컸으나 lipase의 활성 억제는 반대였다. 결론적으로 흰쥐에서 솔잎, 홍차 및 녹차의 항-비만 효과가 관찰되었으며 추출물 혼합물의 항-비만 효과가 같은 조건에서는 가장 컸다. 과체중인에서 추출물 혼합물은 대조군에 비하여 체중 및 체지방 감소효과를 보였다. 홍차와 녹차의 항-비만효과는 부분적으로는 위장관에서 췌장 lipase와 ${\alpha}-amylase$의 활성 억제에 의한 탄수화물과 지방의 소화감소에 기인하는 것으로 생각된다.

• 한국식품과학회지
• /
• 제48권4호
• /
• pp.341-346
• /
• 2016

HPA는 식품으로 섭취되는 녹말을 분해하는데 있어서 매우 중요한 역할을 수행하는 효소이기 때문에 HPA 효소 활성의 억제는 당뇨와 비만과 같은 질환의 예방과 치료에 있어서 의미를 가진다. 따라서 HPA는 당뇨병 치료와 비만 예방을 위한 새로운 식 의약품 소재 개발을 위한 주요 타깃 효소 중 하나이며, 새로운 소재의 개발을 위해서는 HPA의 반응 메커니즘을 비롯하여 천연 기질 분해 특성에 대한 이해가 반드시 필요하다. 본 연구에서는 HPA의 동질효소 중 연구가 거의 진행되지 않은 HPA II에 대한 효소 특성화를 진행하고자 P. pastoris 시스템을 이용하여 재조합 HPA II를 생산하였으며, 녹말 분해와 관련된 효소적 특성을 분석하였다. HPA II는 10 mM NaCl까지 농도 의존적으로 효소활성이 증가하였으며, 최적 활성을 위한 pH는 0 mM NaCl 조건에서 pH 6.5이었으나 10 mM NaCl조건에서 pH 7.5로 이동하는 특성을 보였으며, 이는 HPA I을 포함하는 염소이온 의존형 아밀레이스가 나타내는 전형적인 특징이다. 염소이온 존재 시 최적 pH가 염기성 pH 영역으로 이동하는 것은 염소 이온과 효소의 결합에 의해 HPA II의 산/염기 촉매 잔기의 $pK_a$값이 커진다는 것을 의미하며, 염소이온을 첨가하였을 때 녹말에 대한 가수분해 활성의 증대 정도가 산성 pH 영역보다 염기성 pH 영역에서 두드러지게 나타났다는 점이 이를 뒷받침하였다. 반응속도론적 분석 결과에 따르면 염소이온 존재 시 효소활성의 증대는 대부분 전환수(turnover number)의 증대에 의한 것으로 나타났으며, 가용성 녹말 보다 곡류 녹말에 대한 전환수의 증대가 크게 나타났다. 염소이온은 활성의 증대뿐만 아니라 고농도의 기질 조건에서 기질에 의한 효소 활성 억제 양상을 심화시키는 것으로 나타났다. 결론적으로 HPA II의 특징은 HPA I과 거의 유사한 경향을 나타내었으며, 염소이온 첨가여부에 따른 HPA II의 가수분해활성 결과를 바탕으로 향 후 HPA에 대한 곡류 녹말 가수분해 활성 억제제 개발을 위한 연구를 추진할 계획이다.