Butler D J, De Forest P R, Kobilinsky L
John Jay College of Criminal Justice, City University of New York, NY.
J Forensic Sci. 1990 Mar;35(2):336-44.
Keratins represent the principal structural proteins of hair. They are also found in horn, nail, claw, hoof, and feather. Hair and nail samples from human and canine sources and hair samples from mule deer, white tail deer, cat, moose, elk, antelope, caribou, raccoon, and goat were studied. Parrot and goose feathers were also analyzed. Keratins are polymorphic, and species differences are known to exist. Proteinaceous extracts of deer and antelope antlers and bovine and rhinoceros horn were prepared by solubilizing 10 mg of horn sample in 200 microL of a solution containing 12M urea, 74mM Trizma base, and 78mM dithiothreitol (DTT). Extraction took place over a 48-h period. A 25-microL aliquot of extract was removed and incubated with 5 microL of 0.1 M DTT for 10 min at 25 degrees C. Keratins were then separated by isoelectric focusing (IEF) on 5.2% polyacrylamide gels for 3 h and visualized using silver staining. At least 20 bands could be observed for each species studied. However, band patterns differed in the position of each band, in the number of bands, and in band coloration resulting from the silver staining process. Horn from two species of rhinoceros was examined. For both specimens, most bands occurred in the pH range of 4 to 5. Although similar patterns for both species were observed, they differed sufficiently to differentiate one from the other. As might be expected, the closer two species are related phylogenetically, the greater the similarity in the IEF pattern produced from their solubilized keratin.(ABSTRACT TRUNCATED AT 250 WORDS)
角蛋白是毛发的主要结构蛋白。它们也存在于角、指甲、爪子、蹄和羽毛中。对来自人类和犬类的毛发和指甲样本以及来自骡鹿、白尾鹿、猫、驼鹿、麋鹿、羚羊、驯鹿、浣熊和山羊的毛发样本进行了研究。还分析了鹦鹉和鹅的羽毛。角蛋白具有多态性，已知存在物种差异。通过将10毫克角样本溶解在200微升含有12M尿素、74mM三羟甲基氨基甲烷碱和78mM二硫苏糖醇（DTT）的溶液中，制备鹿和羚羊鹿角以及牛和犀牛角的蛋白质提取物。提取过程持续48小时。取出25微升提取物等分试样，与5微升0.1M DTT在25℃下孵育10分钟。然后通过等电聚焦（IEF）在5.2%聚丙烯酰胺凝胶上分离角蛋白3小时，并使用银染进行可视化。对于每个研究的物种，至少可以观察到20条带。然而，条带模式在每条带的位置、带的数量以及银染过程产生的带颜色方面存在差异。检查了两种犀牛的角。对于两个标本，大多数条带出现在pH值为4至5的范围内。虽然观察到两种物种的模式相似，但它们的差异足以区分彼此。正如预期的那样，两个物种在系统发育上关系越密切，它们溶解的角蛋白产生的IEF模式的相似性就越大。（摘要截断于250字）
