Wang D, Jiang X C, Chen P, Inouchi J, Halpern M
Department of Biochemistry, State University of New York Health Science Center, Brooklyn 11203.
Brain Behav Evol. 1993;41(3-5):246-54. doi: 10.1159/000113846.
We have isolated seven proteins from earthworm preparations that are chemoattractive to garter snakes. Three of these proteins have been purified to homogeneity: two from aqueous earthworm wash (EWW) and one from electric shock-induced earthworm secretion (ESS). One of the two highly purified proteins from EWW has a relative molecular mass of 20 kDa and contains free sulfhydryl groups that appear to play a functional role in its chemoattractivity. The other purified protein from EWW has a molecular mass of 3 kDa (low molecular weight protein, LMW). The highly purified chemoattractive protein (ES20) from ESS is a glycoprotein having a minimum molecular mass of 15.4 kDa calculated from its amino acid and carbohydrate contents. It consists of a single polypeptide chain. The sequence of terminal 15 amino acid residues from its amino (NH2-) terminal has been determined. It binds specifically to the membranes of vomeronasal sensory epithelium in a saturable and reversible fashion with a Kd value of about 0.3 microM and Bmax value of 0.4 nmol/mg of protein. This protein causes an increase in firing rate of individual neurons in the accessory olfactory bulb of garter snakes, the projection site for vomeronasal neurons. All the isolated chemoattractive proteins from both earthworm preparations can be divided immunologically into three groups: (i) those closely related to the ES20 snake-attractive protein, (ii) those closely related to the LMW snake-attractive protein, and (iii) those unrelated to either ES20 or the LMW protein.
我们从蚯蚓提取物中分离出了七种对束带蛇具有化学吸引力的蛋白质。其中三种蛋白质已被纯化至同质：两种来自蚯蚓水洗液（EWW），一种来自电击诱导的蚯蚓分泌物（ESS）。EWW中两种高度纯化的蛋白质之一相对分子质量为20 kDa，含有游离巯基，这些巯基似乎在其化学吸引力中发挥功能作用。EWW中另一种纯化的蛋白质分子量为3 kDa（低分子量蛋白质，LMW）。ESS中高度纯化的化学吸引蛋白（ES20）是一种糖蛋白，根据其氨基酸和碳水化合物含量计算，其最小分子量为15.4 kDa。它由一条多肽链组成。已经确定了其氨基（NH2-）末端的15个氨基酸残基的序列。它以饱和且可逆的方式特异性结合犁鼻器感觉上皮的膜，Kd值约为0.3 microM，Bmax值为0.4 nmol/mg蛋白质。这种蛋白质会导致束带蛇副嗅球中单个神经元的放电频率增加，副嗅球是犁鼻器神经元的投射部位。从两种蚯蚓提取物中分离出的所有化学吸引蛋白在免疫学上可分为三组：（i）与ES20蛇吸引蛋白密切相关的那些，（ii）与LMW蛇吸引蛋白密切相关的那些，以及（iii）与ES20或LMW蛋白均无关的那些。
