SUBSTRATE-SPECIFICITY OF SMALL-INTESTINAL LACTASE - STUDY OF THE STERIC EFFECTS AND HYDROGEN-BONDS INVOLVED IN ENZYME-SUBSTRATE INTERACTION

被引:22
作者
FERNANDEZ, P [1 ]
CANADA, FJ [1 ]
JIMENEZBARBERO, J [1 ]
MARTINLOMAS, M [1 ]
机构
[1] CSIC,INST QUIM ORGAN,CARBOHIDRATOS GRP,E-28006 MADRID,SPAIN
关键词
INTESTINAL LACTASE; METHYL BETA-LACTOSIDE; GALACTOSIDASE; SUBSTRATE SPECIFICITY; MOLECULAR RECOGNITION;
D O I
10.1016/0008-6215(95)00034-Q
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Milk lactose is hydrolysed to D-galactose and D-glucose in the small intestine of mammals by the lactase-phlorizin hydrolase complex (LPH, EC 3.2.1.23-62). Lactase activity has broad substrate selectivity and several glycosides are substrates. Recently, using the monodeoxy derivatives of methyl beta-lactoside (1), we have shown the importance of each hydroxyl group in the substrate molecule concerning the interaction with the enzyme. Now we have studied the corresponding O-methyl derivatives, as well as some of the halo derivatives of 1. We have found that the enzyme presents steric restrictions to the recognition of substrates modified in the galactose moiety. In contrast, the binding site for the aglycon part of the substrate is looser. On the other hand, we have previously shown that HO-3' and HO-6 were important for the recognition of the substrate by the enzyme. Now we have found that the corresponding fluorine derivatives are not, or very poorly, recognized. This suggests that the HO-3' and HO-6 participate, as donors, in hydrogen bonds in the interaction with the enzyme.
引用
收藏
页码:31 / 42
页数:12
相关论文
共 40 条
  • [11] PHYSICOCHEMICAL CHARACTERIZATION OF HUMAN INTESTINAL LACTASE
    LAU, HKF
    [J]. BIOCHEMICAL JOURNAL, 1987, 241 (02) : 567 - 572
  • [12] LEATHERBARROW RJ, 1987, ENZFITTER ELSEVIER B
  • [13] LEESE HJ, 1973, J BIOL CHEM, V248, P8170
  • [14] THE ORIGIN OF THE SPECIFICITY IN THE RECOGNITION OF OLIGOSACCHARIDES BY PROTEINS
    LEMIEUX, RU
    [J]. CHEMICAL SOCIETY REVIEWS, 1989, 18 (03) : 347 - 374
  • [15] LOWRY OH, 1951, J BIOL CHEM, V193, P265
  • [16] PHLORIZIN HYDROLASE - A BETA-GLUCOSIDASE OF HAMSTER INTESTINAL BRUSH BORDER MEMBRANE
    MALATHI, P
    CRANE, RK
    [J]. BIOCHIMICA ET BIOPHYSICA ACTA, 1969, 173 (02) : 245 - +
  • [17] COMPLETE PRIMARY STRUCTURE OF HUMAN AND RABBIT LACTASE-PHLORIZIN HYDROLASE - IMPLICATIONS FOR BIOSYNTHESIS, MEMBRANE ANCHORING AND EVOLUTION OF THE ENZYME
    MANTEI, N
    VILLA, M
    ENZLER, T
    WACKER, H
    BOLL, W
    JAMES, P
    HUNZIKER, W
    SEMENZA, G
    [J]. EMBO JOURNAL, 1988, 7 (09) : 2705 - 2713
  • [18] INTESTINAL LACTASE EVALUATION INVIVO WITH 3-METHYLLACTOSE
    MARTINEZPARDO, M
    MONTES, PG
    MARTINLOMAS, M
    SOLS, A
    [J]. FEBS LETTERS, 1979, 98 (01) : 99 - 102
  • [19] MOLECULAR RECOGNITION .10. A NOVEL PROCEDURE FOR THE DETECTION OF THE INTERMOLECULAR HYDROGEN-BONDS PRESENT IN A PROTEIN-BULLET-OLIGOSACCHARIDE COMPLEX
    NIKRAD, PV
    BEIERBECK, H
    LEMIEUX, RU
    [J]. CANADIAN JOURNAL OF CHEMISTRY-REVUE CANADIENNE DE CHIMIE, 1992, 70 (01): : 241 - 253
  • [20] LACTASE-PHLORIZIN HYDROLASE COMPLEX FROM MONKEY SMALL-INTESTINE - PURIFICATION, PROPERTIES AND EVIDENCE FOR 2 CATALYTIC SITES
    RAMASWAMY, S
    RADHAKRISHNAN, AN
    [J]. BIOCHIMICA ET BIOPHYSICA ACTA, 1975, 403 (02) : 446 - 455