- 作者: 葉東柏; 蘇仲卿
- 作者服務機構: 國立臺灣大學農業化學系; 中央研究院生物化學研究所
- 中文摘要:
純重型尿激?經等電焦集電泳法可分離出三種異構?,其等電點分別為9.9(約佔70%),8.9及8.35。然而此等
異構?及重型尿激?之氨基酸組成及胜?指膜圖頗為類似。由醣質分析顯示異構?間之差異在於涎酸含量之高低,而且
於低離子強度與高醣含量的介質中,酵素分子可與鳳醣質結合。在動力學參數方面,本文利用尿激?之一種特異性合成胜
?基質顯示此等異構?之最適pH在8.5~8.8之間,表麥米氏參數(Km)1.09~ 2.78 mM,及最大反應速率為10.5~
13.2 μ mol/min/IU。
0 - 英文摘要: When the purified L-UK was further separated by preparative isoelectrio-focusing electrophoresis,three forms different in pI values (9.9,8.9 and 8.35)could be obtained. The chemical compositions and some other molecular and kinetic parameters (using benzoyl-L-valyl-glycyl-L-arginine-p-nitroanilide (BVGANA) or plasminogen as substrate) of the multiforms of L-UK wereassessed and compared. From these data, several valuable findings were obtained as follows: 1) Although the total number of acidic amino acid residues was 1.1 to 1.2 fold larger than the sumof basic amino acid residues, the high pI values of L-UK forms (8.4 to 9.9) suggested the presence of acidicamino acid in their amide form in a large proportion. 2) The difference in pIs of the different L-UK forms was mainly due to the difference in sialic acidcontent. 3) Glucose (or sucrose) was found in the resolved L-UK forms but not in the original 1-UK unresolv-ed. It indicated that sugar might be adsorbed onto the enzyme molecule in a low ionic strength and highsugar content medium. 4) A sugar content pattern (but not amino acid content) distinctly different from those publishedby others was obtained. This discrepancy might be due to the difference in the sources of enzyme prepara-tions. 5) The similarity in the kinetic parameters suggested that the different forms of L-UK have a similaraffinity toward the substrate used (BVGANA and plasminogen).
- 中文關鍵字: --
- 英文關鍵字: --