本文件提供了低蛋白天然橡胶（LPNR）规范的指南和要求。根据天然橡胶含量的来源，提出了一种分级系统，并通过酶和非酶两种工艺来区分，用于去除蛋白质。

This document provides guidelines and gives requirements on the specification of low protein natural rubber (LPNR). A grading system is proposed, based on the origin of the natural rubber content and differentiated by the two processes, enzymatic and non-enzymatic, applied for removal of the proteins.